Wiring & Schematic Diagram Symbols and Meanings
Browse 482 electrical and electronic symbols with meanings, terminals, example circuits, and verified IEC or ANSI notes where available. Public reference pages are free to browse; editor pack access depends on the current plan.
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DIY & Residential symbols
| Symbol | Meaning |
|---|---|
| 240V Outlet symbol | The 240V Outlet symbol represents a 240-volt alternating-current receptacle used in residential and commercial wiring diagrams to indicate a high-voltage outlet supplying large ap… |
| AFCI Breaker symbol | The AFCI Breaker symbol represents an Arc-Fault Circuit Interrupter circuit breaker in residential and commercial wiring diagrams, denoting a protective device that detects the un… |
| AFCI/GFCI Combo Breaker symbol | The AFCI/GFCI Combo Breaker symbol represents a dual-protection circuit breaker that combines Arc-Fault Circuit Interrupter (AFCI) and Ground-Fault Circuit Interrupter (GFCI) func… |
| Alarm Panel symbol | The Alarm Panel symbol represents the control unit of an intrusion alarm system — drawn as a rectangle with a keypad dot grid and zone terminal marks — with terminals for AC input… |
| Armored Cable (MC/BX) symbol | The Armored Cable (MC/BX) symbol represents a type of electrical wiring in which insulated conductors are enclosed within a flexible metallic sheath — either metal-clad (MC) or ar… |
| Attic Fan symbol | The Attic Fan symbol represents an electrically powered ventilation fan installed in an attic, gable, or roof space to exhaust hot air from the building's upper zone, shown in res… |
| Baseboard Heater symbol | The Baseboard Heater symbol represents a fixed electric resistance convection heater — drawn as a long, low rectangle with a heating-element zigzag inside per the IEC 60617 resist… |
| Bathroom Exhaust Fan symbol | The Bathroom Exhaust Fan symbol represents a ceiling- or wall-mounted ventilation fan used in wiring diagrams to show a switched 120 V load that exhausts humid or stale air from a… |
| Battery Bank symbol | The Battery Bank symbol represents multiple storage batteries connected as one DC source — drawn as two battery cell symbols (long/short parallel line pairs, per IEC 60617) side b… |
| CCTV Camera symbol | The CCTV Camera symbol represents a fixed surveillance camera — drawn as a trapezoid camera body with a lens circle and mounting line — with power terminals (12V+/PoE, GND) and a… |
| Ceiling Fan symbol | The Ceiling Fan symbol represents a ceiling-mounted motor-driven ventilation fan — depicted in residential and commercial wiring diagrams per ANSI/NFPA 70 (NEC) drawing convention… |
| Ceiling Fan with Light symbol | The Ceiling Fan with Light symbol represents a combined ceiling-mounted fan and integral light kit — shown in residential wiring diagrams per NEC Article 422 — with three independ… |
| Circuit Breaker symbol | The Circuit Breaker symbol represents an automatically operated electrical switch designed to interrupt fault current and protect a circuit from damage caused by overcurrent or sh… |
| CO Detector symbol | The CO Detector symbol represents a carbon monoxide detection and alarm device — required by NFPA 720, UL 2034, and IEC 60335-2-90 — depicted in residential and commercial electri… |
| Conduit Run symbol | The Conduit Run symbol represents a section of electrical raceway — drawn as a single or double line with annotations indicating conduit type, trade size, and routing path — used… |
| Dimmer Switch symbol | The Dimmer Switch symbol represents a variable light-control device in wiring diagrams, depicted as a standard switch symbol combined with a variable-element arrow or arc, used to… |
| Disconnect symbol | The Disconnect symbol represents a manually operated safety switching device in wiring diagrams that provides visible, lockable isolation of electrical equipment from its power so… |
| Doorbell / Chime symbol | The Doorbell / Chime symbol represents the sounder or chime unit in a residential low-voltage doorbell wiring diagram, depicting the device that produces an audible alert when a r… |
| Doorbell Button symbol | The Doorbell Button symbol represents a normally-open (NO) momentary pushbutton switch in residential wiring diagrams that, when pressed, briefly closes the low-voltage circuit be… |
| Doorbell Camera symbol | The Doorbell Camera symbol represents a smart video doorbell device in residential and commercial wiring diagrams that combines a doorbell pushbutton, wide-angle camera, microphon… |
| Double-Pole Breaker symbol | The Double-Pole Breaker symbol represents a two-pole circuit breaker in residential and light commercial wiring diagrams that simultaneously interrupts both ungrounded (hot) condu… |
| Dual Run Capacitor symbol | The Dual Run Capacitor symbol represents two motor-run capacitors sharing one can and one common terminal — drawn as a round can outline with two capacitor plate pairs inside and… |
| Duplex Outlet symbol | The Duplex Outlet symbol represents a standard dual-receptacle 120 V AC wall socket used in residential and commercial wiring diagrams, defined under ANSI/NFPA 70 (National Electr… |
| Electric Cooker / Range symbol | The Electric Cooker / Range symbol represents a high-power fixed cooking appliance — drawn as a square with four hob circles — with L1, L2, Neutral, and Earth terminals, supplied… |
| Emergency Light symbol | The Emergency Light symbol represents a self-contained battery-backup egress lighting unit — drawn as a rectangle with two lamp heads on top and a battery cell inside — with Hot,… |
| EV Charger Outlet (NEMA 14-50) symbol | The EV Charger Outlet (NEMA 14-50) symbol represents a 240 V AC, 50 A, 4-wire receptacle used as the connection point for Level 2 electric vehicle charging equipment (EVSE), as de… |
| Exit Sign symbol | The Exit Sign symbol represents a continuously illuminated, battery-backed egress marking fixture — drawn as a rectangle containing the word EXIT (or the ISO 7010 'running man' pi… |
| Fence Energizer symbol | The Fence Energizer symbol represents the pulse generator of an electric fence — drawn as a rectangle with a lightning-bolt mark, mains input terminals (AC L, AC N), a high-voltag… |
| Fluorescent Fixture symbol | The Fluorescent Fixture symbol represents a gas-discharge lighting unit containing one or more fluorescent tubes (T8 or similar) driven by a ballast, shown in electrical wiring di… |
| Garage Door Opener symbol | The Garage Door Opener symbol represents a motor-driven residential or commercial door operator unit that raises and lowers a sectional or roll-up garage door, shown in electrical… |
| Garbage Disposal symbol | The Garbage Disposal symbol represents an electrically-powered kitchen food-waste disposer unit installed under a sink that uses a motor-driven impeller to grind food scraps into… |
| Gate Motor symbol | The Gate Motor symbol represents an electromechanical gate operator — drawn as a motor circle marked 'M' inside a rectangle suggesting the rack-and-pinion track — with low-voltage… |
| Generator symbol | The Generator symbol represents an electromechanical device that converts mechanical energy into electrical energy using electromagnetic induction, shown in circuit diagrams and s… |
| GFCI Breaker symbol | The GFCI Breaker symbol represents a combination circuit breaker and ground-fault current interrupter installed in a load-center panel that simultaneously provides overcurrent pro… |
| GFCI Outlet symbol | The GFCI Outlet symbol represents a Ground Fault Circuit Interrupter receptacle — a mains-voltage outlet with built-in current-sensing electronics that trips within 25 millisecond… |
| Ground symbol | The Ground symbol represents the reference node in a circuit diagram at which voltage is defined as zero volts (0 V), drawn as a series of three or more decreasing-length horizont… |
| Hot Tub Disconnect symbol | The Hot Tub Disconnect symbol represents a listed outdoor disconnect means — typically a lockable non-fusible or fusible safety switch with integral ground-fault circuit interrupt… |
| Junction Box symbol | The Junction Box symbol represents an enclosed electrical enclosure in wiring diagrams used to house and protect wire splice connections, drawn as a square or rectangle with conne… |
| Landscape Light (Low Voltage) symbol | The Landscape Light (Low Voltage) symbol represents a low-voltage outdoor luminaire in wiring diagrams, typically a 12 V AC/DC pathway, accent, or spot light, drawn as a labeled f… |
| LED Driver symbol | The LED Driver symbol represents the AC-to-DC power conversion unit that supplies regulated voltage or current to LED loads — drawn as a rectangle with 'LED DRV' text or a diode m… |
| LED Strip symbol | The LED Strip symbol represents a flexible low-voltage tape of series-parallel LED groups — drawn as a long thin rectangle containing LED (diode-with-arrows) marks and dashed cut… |
| Light Fixture symbol | The Light Fixture symbol (also called a luminaire symbol) represents a permanently wired ceiling, wall, or surface-mounted electric light fitting — typically drawn as a circle wit… |
| Low Voltage Transformer symbol | The Low Voltage Transformer symbol represents a step-down isolation transformer that converts 120 V AC mains voltage to a low-voltage AC output (typically 24 V AC), classified as… |
| Main Panel symbol | The Main Panel symbol represents the primary electrical distribution panel (also called the load centre, breaker box, or service entrance panel) that receives utility power at the… |
| Meter Base symbol | The Meter Base symbol represents the utility-owned socket enclosure mounted at the service entrance that accepts a kilowatt-hour (kWh) revenue meter, connecting the incoming servi… |
| Motion Sensor symbol | The Motion Sensor symbol represents a detection device — most commonly a passive infrared (PIR) sensor or microwave detector — that outputs a signal when movement is detected with… |
| Occupancy Sensor symbol | The Occupancy Sensor symbol represents an electronic detection device that automatically controls lighting or HVAC systems based on the presence or absence of people in a space, d… |
| Outdoor Lamp Post symbol | The Outdoor Lamp Post symbol represents a freestanding exterior luminaire mounted on a vertical post — used in residential and commercial landscape wiring diagrams to indicate a y… |
| Outlet symbol | The Outlet symbol (also called a receptacle or socket symbol) represents a fixed electrical socket mounted in a wall, panel, or floor box — drawn as a circle with two or three slo… |
| Path Light symbol | The Path Light symbol represents a low-voltage landscape luminaire installed along walkways, garden paths, or driveways — used in landscape and exterior wiring diagrams to indicat… |
| Photocell / Dusk Sensor symbol | The Photocell / Dusk Sensor symbol represents an automatic light-control device, designated P or LS in schematics, that uses a light-dependent switching mechanism to turn connecte… |
| Pool Pump symbol | The Pool Pump symbol represents a single-phase electric motor-driven centrifugal pump used in swimming-pool and spa filtration systems, depicted in wiring and schematic diagrams a… |
| Prepaid Meter symbol | The Prepaid Meter symbol represents a pay-before-use kWh energy meter with an integral supply switch — drawn as a meter rectangle with a digital display band and keypad dots — wit… |
| Pull Box symbol | The Pull Box symbol represents an enclosed metal or non-metallic junction enclosure installed in a conduit system to facilitate wire pulling, splicing, and routing of conductors b… |
| Range / Dryer Outlet symbol | The Range / Dryer Outlet symbol represents a 240 V AC (or 120/240 V AC) heavy-duty receptacle for connecting an electric range, cooktop, or clothes dryer, depicted in electrical w… |
| Range Hood symbol | The Range Hood symbol represents an electrically powered kitchen exhaust ventilation appliance that captures cooking vapours, grease, and odours at the cooktop and exhausts them o… |
| Recessed Can Light (6-inch) symbol | The Recessed Can Light (6-inch) symbol represents a 6-inch diameter recessed luminaire — also called a can light, downlight, or pot light — installed flush within a ceiling cavity… |
| Recessed Light symbol | The Recessed Light symbol represents a recessed ceiling luminaire — also called a can light, downlight, or pot light — mounted flush within the ceiling surface, depicted in electr… |
| Romex Cable symbol | The Romex Cable symbol represents a non-metallic sheathed (NM-B) electrical cable used in residential wiring, depicted as a single line or paired conductors enclosed in a sheath a… |
| Service Entrance symbol | The Service Entrance symbol represents the utility supply interface point in an electrical wiring diagram — the point at which the electrical utility's conductors enter a building… |
| Smart Switch (WiFi) symbol | The Smart Switch (WiFi) symbol represents a WiFi-connected electronically-controlled switch module used in IoT and smart-home wiring diagrams to denote a device that can open or c… |
| Smoke Detector symbol | The Smoke Detector symbol represents a life-safety sensing device in electrical and fire-alarm wiring diagrams that detects airborne combustion particles and sounds an alarm, draw… |
| Solar Charge Controller symbol | The Solar Charge Controller symbol represents the DC power regulator between a photovoltaic array and a battery bank — drawn as a rectangle with sun-in/battery-out marks (often la… |
| Solar Inverter symbol | The Solar Inverter symbol represents a grid-tie or off-grid photovoltaic inverter drawn as a labeled rectangle with DC input terminals (DC+ and DC−) and AC output terminals (AC L… |
| Solar Panel symbol | The Solar Panel symbol represents a photovoltaic module drawn as a rectangular grid with two output terminals (+ and −), denoting an assembly of solar cells connected in series an… |
| Subpanel symbol | The Subpanel symbol represents a secondary electrical distribution panel — also called a sub-distribution board or load centre — fed from a main service panel via a feeder circuit… |
| Switch (3-Way) symbol | The Switch (3-Way) symbol represents a single-pole double-throw (SPDT) wall switch used in residential and commercial wiring to control a lighting fixture from two separate locati… |
| Switch (SPST) symbol | The Switch (SPST) symbol represents a Single-Pole Single-Throw switch — a two-terminal device that either completes or breaks a single current path — drawn as a short angled line… |
| Tandem / Twin Breaker symbol | The Tandem / Twin Breaker symbol represents a half-size double circuit breaker that occupies a single panel slot while providing two independent overcurrent protection circuits, e… |
| Thermostat symbol | The Thermostat symbol represents a temperature-activated switching or control device—depicted in wiring diagrams as a box or block labelled with its terminal designations (RH, W,… |
| Timer Switch symbol | The Timer Switch symbol represents a time-controlled switching device—drawn as a rectangle or box with a clock face or timing indicator and In/Out terminals—that automatically ope… |
| Track Light symbol | The Track Light symbol represents a linear lighting system—drawn in electrical and lighting layout diagrams as a horizontal line (the track rail) with one or more spotlights or ar… |
| Track Lighting Head symbol | The Track Lighting Head symbol represents an individual adjustable-aim luminaire fixture—drawn as a small circle or arrowhead with Hot and Neutral terminal connections—that mounts… |
| Transfer Switch symbol | The Transfer Switch symbol represents an electrical switching device—drawn as a three-terminal block or double-throw switch with terminals labelled Utility (normal supply), Load (… |
| Under-Cabinet Light symbol | The Under-Cabinet Light symbol represents a low-profile, hardwired or plug-in luminaire mounted beneath kitchen cabinets or shelving to provide focused task lighting, shown in res… |
| USB Outlet symbol | The USB Outlet symbol represents a mains wall receptacle that incorporates one or more built-in USB charging ports alongside (or in place of) standard AC sockets, shown on residen… |
| Weatherproof Box symbol | The Weatherproof Box symbol represents an outdoor-rated electrical enclosure used in wiring diagrams to denote a junction box, outlet box, or device box fitted with a cover that p… |
| Weatherproof Outlet symbol | The Weatherproof Outlet symbol represents an outdoor-rated electrical receptacle installed in a sealed enclosure with a moisture-resistant cover, used in wiring diagrams to denote… |
| Whole House Surge Protector symbol | The Surge Protector symbol represents a point-of-use Surge Protective Device (SPD Type 3) connected between a line conductor and ground that clamps transient overvoltages from lig… |
| Whole-House Fan symbol | The Whole-House Fan symbol represents a large ceiling-mounted ventilation fan used in residential wiring diagrams to denote a motor-driven unit installed in an attic floor or hall… |
| Wire Nut symbol | The Wire Nut symbol represents a twist-on wire connector used in wiring diagrams to denote the physical splice point where two or more conductors are joined by a colour-coded insu… |
| Wire Raceway / Molding symbol | The Wire Raceway / Molding symbol represents a surface-mounted cable management channel used in wiring diagrams to denote a flat-profile plastic or metal enclosure that routes and… |
| Wire Splice symbol | The Wire Splice symbol represents a permanent electrical connection between two conductor ends in a wiring diagram, used to denote an in-line joint where two wire segments are joi… |
| Zone Valve symbol | The Zone Valve symbol represents a motorized valve that opens and closes hot-water flow to one heating zone in a hydronic system, drawn as a valve body (two triangles tip-to-tip)… |
Hobbyist & Electronics symbols
| Symbol | Meaning |
|---|---|
| 4x4 Matrix Keypad symbol | The 4×4 Matrix Keypad symbol represents a 16-key input device organised in four rows and four columns, where each key connects one row line to one column line, used in circuit dia… |
| 555 Timer IC symbol | The 555 Timer IC symbol represents a versatile monolithic timing integrated circuit — originally designated NE555 by Signetics in 1972 — shown in circuit diagrams as a rectangular… |
| 74HC595 Shift Register symbol | The 74HC595 Shift Register symbol represents an 8-bit serial-in, parallel-out (SIPO) shift register integrated circuit that converts a serial SPI-compatible data stream into eight… |
| 8-Channel Relay Board symbol | The 8-Channel Relay Board symbol represents a pre-assembled module containing eight independent electromechanical relays driven by optocoupler-isolated control inputs, depicted in… |
| 8x8 LED Matrix symbol | The 8×8 LED Matrix symbol represents a 64-LED display module arranged in an 8-row by 8-column grid, where each LED sits at a row-column intersection and is individually addressed… |
| A4988 Stepper Driver symbol | The A4988 Stepper Driver symbol represents a bipolar stepper motor driver module drawn as a labeled rectangle with control input pins (STEP, DIR, EN, VMOT) on the left and motor c… |
| ACS712 Current Sensor Module symbol | The ACS712 Current Sensor Module symbol represents a Hall-effect-based integrated current sensing module that produces an analogue output voltage proportional to the AC or DC curr… |
| ADS1115 ADC Module symbol | The ADS1115 ADC Module symbol represents a precision 16-bit, 4-channel, I2C-interface analog-to-digital converter module based on the Texas Instruments ADS1115 IC, shown in circui… |
| Arduino Uno symbol | The Arduino Uno symbol represents the Arduino Uno R3 microcontroller development board — a popular open-source hardware platform based on the ATmega328P microcontroller — shown in… |
| ATmega328 (DIP) symbol | The ATmega328 (DIP) symbol represents the Microchip (formerly Atmel) ATmega328P 8-bit AVR microcontroller in a 28-pin dual in-line package (DIP-28), shown in circuit schematics as… |
| Battery symbol | The Battery symbol represents a DC voltage source composed of one or more electrochemical cells, drawn as alternating long-and-short parallel vertical lines (one cell per long-sho… |
| Bluetooth Module (HC-05) symbol | The Bluetooth Module (HC-05) symbol represents a serial-to-Bluetooth bridge IC module used in circuit diagrams to show a wireless communication peripheral that translates UART ser… |
| BMP280 Pressure Sensor symbol | The BMP280 Pressure Sensor symbol represents a Bosch Sensortec digital barometric pressure and temperature sensor IC used in circuit diagrams as a rectangular module block with VC… |
| Boost Converter Module symbol | The Boost Converter Module symbol represents a DC-DC step-up power module that raises an input voltage to a higher output voltage using switched-mode power conversion, shown in ci… |
| Breadboard Power Rail symbol | The Breadboard Power Rail symbol represents the dual-bus power distribution row on a solderless breadboard that distributes VCC (positive supply) and GND (ground) along the full l… |
| Buck Converter Module symbol | The Buck Converter Module symbol represents a DC-DC step-down power module that reduces an input voltage to a lower regulated output voltage using switched-mode power conversion,… |
| CAN Bus Transceiver symbol | The CAN Bus Transceiver symbol represents an integrated circuit — such as the Microchip MCP2551 or TI SN65HVD230 — that interfaces a microcontroller's single-ended CAN TX/RX logic… |
| Capacitive Touch Sensor symbol | The Capacitive Touch Sensor symbol represents a proximity-sensing module—drawn as a rectangular block with three terminals labelled VCC (power supply), GND (ground), and OUT (digi… |
| Capacitor symbol | The Capacitor symbol represents a passive two-terminal component that stores electrical energy in an electric field, drawn as two parallel lines (non-polarised) or one straight li… |
| CD4051 Analog MUX symbol | The CD4051 Analog MUX symbol represents an 8-to-1 analog multiplexer/demultiplexer integrated circuit that uses three binary select inputs to route one of eight analog or digital… |
| Cell (Single) symbol | The Cell symbol represents a single electrochemical cell — the basic unit of DC supply — drawn per IEC 60617 as one long thin line (positive terminal, +) parallel to one short thi… |
| Crystal Oscillator symbol | The Crystal Oscillator symbol represents a quartz crystal resonator — drawn as a rectangle (the piezoelectric element) flanked by two vertical lines (the electrodes) with connecti… |
| Current Sensor (ACS712) symbol | The Current Sensor (ACS712) symbol represents a Hall-effect-based linear current sensor integrated circuit manufactured by Allegro MicroSystems, shown in circuit diagrams with thr… |
| DC Barrel Jack symbol | The DC Barrel Jack symbol represents a coaxial power connector—consisting of a cylindrical sleeve (negative/ground) and a central pin (positive)—used to supply DC power to electro… |
| DC Motor symbol | The DC Motor symbol represents a direct-current electric motor — drawn as a circle containing the letter M (and often an equals sign = to denote DC) — that converts direct-current… |
| DHT11 Temperature/Humidity symbol | The DHT11 Temperature/Humidity symbol represents a low-cost digital sensor module that measures ambient temperature (0–50 °C) and relative humidity (20–90 % RH) and transmits cali… |
| Diode symbol | The Diode symbol represents a two-terminal semiconductor device that allows current to flow predominantly in one direction — from anode to cathode — drawn as a filled triangle wit… |
| DIP Switch symbol | The DIP Switch symbol represents an array of independent SPST switches packaged in a dual in-line package — here a 4-way unit with eight terminals (1 In/1 Out through 4 In/4 Out,… |
| DPDT Switch symbol | The DPDT Switch symbol represents a double-pole, double-throw switch — two electrically independent SPDT changeover contacts operated by one actuator — drawn per IEC 60617 as two… |
| DS18B20 Temperature Sensor symbol | The DS18B20 Temperature Sensor symbol represents Maxim Integrated's (now Analog Devices) DS18B20 digital programmable-resolution 1-Wire temperature sensor IC in electronic schemat… |
| Electric Bell symbol | The Electric Bell symbol represents an electromagnetically operated audible signalling device with two non-polarised terminals (A, B), drawn per IEC 60617 as a semicircular dome s… |
| Electrolytic Capacitor symbol | The Electrolytic Capacitor symbol represents a polarised capacitor that uses an electrolyte to achieve high capacitance in a compact package, depicted in IEC 60617 as two parallel… |
| ESP32 symbol | The ESP32 symbol represents the Espressif Systems ESP32 dual-core 32-bit microcontroller module with integrated 2.4 GHz Wi-Fi (802.11 b/g/n) and Bluetooth Classic / BLE 4.2, depic… |
| ESP8266 Module symbol | The ESP8266 Module symbol represents the Espressif Systems ESP8266 single-core 80/160 MHz Wi-Fi SoC module (commonly used as NodeMCU or ESP-01), providing 2.4 GHz 802.11 b/g/n wir… |
| Ferrite Bead symbol | The Ferrite Bead symbol represents a passive two-terminal EMI suppression component that attenuates high-frequency noise on power supply and signal lines by presenting a high impe… |
| Fingerprint Sensor symbol | The Fingerprint Sensor symbol represents a biometric identification module (such as the R307 or FPM10A series) that optically or capacitively captures a fingerprint image, extract… |
| Fuse symbol | The Fuse symbol represents a protective two-terminal device that interrupts a circuit by melting its conductive element when current exceeds a specified rating, drawn as a short h… |
| Galvanometer symbol | The Galvanometer symbol represents a sensitive moving-coil instrument for detecting and measuring small electric currents, drawn per IEC 60617 indicating-instrument convention as… |
| H-Bridge IC (L298N) symbol | The H-Bridge IC (L298N) symbol represents the STMicroelectronics L298N dual full-bridge motor driver integrated circuit — a monolithic IC containing two independent H-bridge power… |
| Hall Effect Sensor symbol | The Hall Effect Sensor symbol represents a three-terminal semiconductor transducer — with VCC (supply), GND, and OUT pins — that produces a voltage output proportional to, or a di… |
| HC-SR501 PIR Module symbol | The HC-SR501 PIR Module symbol represents a passive infrared motion-detection module drawn as a labeled square with concentric circles indicating the sensor lens and three pins (V… |
| Header Pins (Female) symbol | The Header Pins (Female) symbol represents a multi-pin socket connector — with receptacle contacts designed to receive male header pins — used in electronic schematics to show a t… |
| Header Pins (Male) symbol | The Header Pins (Male) symbol represents a row of protruding male pin connectors — typically 2.54 mm pitch — used in schematics and wiring diagrams to denote a through-hole or sur… |
| Inductor / Coil symbol | The Inductor (Coil) symbol represents a passive component that stores energy in a magnetic field — drawn as a series of arched loops or humps (ANSI Y32.2 / IEEE 315) or as a fille… |
| IR Receiver symbol | The IR Receiver symbol represents a three-terminal integrated infrared demodulator module — such as the TSOP1738 or VS1838B — that detects 38 kHz modulated infrared light from a r… |
| IR Remote Control symbol | The IR Remote Control symbol represents a handheld infrared transmitter device used in circuit diagrams to indicate a remote-control signal source that encodes commands as modulat… |
| IR Transmitter LED symbol | The IR Transmitter LED symbol represents an infrared-emitting diode (IRED) in circuit diagrams, drawn as the standard diode triangle-and-bar glyph with two diagonal emission arrow… |
| Joystick Module symbol | The Joystick Module symbol represents a dual-axis analog input device in circuit diagrams, drawn as a labeled block with pins VCC, GND, VRX (X-axis voltage), and VRY (Y-axis volta… |
| JST Connector (2-pin) symbol | The JST Connector (2-pin) symbol represents a 2-pole miniature wire-to-board or wire-to-wire connector from JST's PH, XH, or SH series in circuit diagrams, drawn as a labeled conn… |
| JST Connector (4-pin) symbol | The JST Connector (4-pin) symbol represents a 4-circuit miniature wire-to-board connector from JST's PH, XH, or SH series in circuit diagrams, drawn as a labeled connector block w… |
| Lamp / Light Bulb symbol | The Lamp / Light Bulb symbol represents a two-terminal light-emitting load (Terminals A and B, non-polarised), drawn per IEC 60617 as a circle with an inscribed X (diagonal cross)… |
| LCD 16x2 Module symbol | The LCD 16x2 Module symbol represents a Hitachi HD44780-compatible alphanumeric liquid-crystal display module capable of showing 16 characters per line across 2 lines, connected i… |
| LED symbol | The LED (Light-Emitting Diode) symbol represents a polarised semiconductor device that emits light when forward-biased current flows from its anode to its cathode, drawn as a fill… |
| LiPo Battery symbol | The LiPo Battery symbol represents a rechargeable lithium polymer electrochemical cell or pack delivering a nominal voltage of 3.7 V per cell (fully charged 4.2 V, minimum dischar… |
| LiPo Charger Module (TP4056) symbol | The LiPo Charger Module (TP4056) symbol represents a lithium-ion/lithium-polymer battery charging module—drawn as a rectangular block with four terminals labelled VCC (USB/input p… |
| LM2596 Power Module symbol | The LM2596 Power Module symbol represents a buck (step-down) switching voltage regulator module based on the LM2596 controller IC, depicted in circuit diagrams as a labelled recta… |
| LM317 (Adjustable Regulator) symbol | The LM317 symbol represents a three-terminal adjustable positive linear voltage regulator IC that delivers an output voltage continuously variable from 1.25 V to 37 V, set by two… |
| LM7805 (5V Regulator) symbol | The LM7805 symbol represents a three-terminal fixed positive 5 V linear voltage regulator IC that delivers a regulated 5.0 V DC output from an input voltage of 7–35 V at up to 1 A… |
| Load Cell (HX711) symbol | The Load Cell (HX711) symbol represents a strain-gauge transducer paired with an HX711 24-bit analogue-to-digital converter, used in circuit diagrams to indicate a sensor that con… |
| Logic Level Shifter symbol | The Logic Level Shifter symbol represents a bidirectional or unidirectional voltage-translation module that allows digital signals from a low-voltage domain (typically 3.3 V, pin… |
| LoRa Module symbol | The LoRa Module symbol represents a long-range, low-power wireless transceiver module based on Semtech's LoRa (Long Range) chirp-spread-spectrum modulation — typically an SX1276/S… |
| MAX7219 LED Driver symbol | The MAX7219 LED Driver symbol represents the Maxim Integrated MAX7219 serialised 8-digit LED display driver IC, which controls up to 64 individual LEDs (as an 8×8 matrix or eight… |
| MCP23017 GPIO Expander symbol | The MCP23017 GPIO Expander symbol represents a 16-bit I2C-controlled bidirectional digital I/O port expander integrated circuit that adds 16 independently configurable general-pur… |
| Microphone symbol | The Microphone symbol represents a transducer that converts acoustic sound pressure waves into an electrical signal, used in circuit and schematic diagrams to indicate an audio in… |
| Motor Driver Module symbol | The Motor Driver Module symbol represents an integrated PWM motor controller IC or module — such as the TB6612FNG or DRV8833 — that accepts low-current logic control signals (IN1,… |
| MPU6050 IMU Module symbol | The MPU6050 IMU Module symbol represents the InvenSense MPU-6050 6-axis inertial measurement unit — a combined 3-axis gyroscope and 3-axis accelerometer on a single chip — depicte… |
| MQ-2 Gas Sensor symbol | The MQ-2 Gas Sensor symbol represents a resistive chemo-resistive gas detection module that responds to combustible gases, smoke, and LPG by varying its internal resistance, shown… |
| N-Channel MOSFET symbol | The N-Channel MOSFET symbol represents an enhancement-mode n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) defined in IEC 60617-05 and ANSI Y32.2 / IEEE 315,… |
| Neon Lamp symbol | The Neon Lamp symbol represents a two-electrode gas-discharge glow lamp with non-polarised terminals A and B, drawn per IEC 60617 gas-filled-lamp convention as a circle containing… |
| NeoPixel LED Ring symbol | The NeoPixel LED Ring symbol represents an Adafruit WS2812B-based addressable RGB LED ring module in which each LED contains an integrated driver IC, allowing full-colour individu… |
| NPN Transistor (BJT) symbol | The NPN Transistor (BJT) symbol represents an N-P-N bipolar junction transistor — a three-terminal semiconductor device in which a small base current controls a larger collector-t… |
| nRF24L01 RF Module symbol | The nRF24L01 RF Module symbol represents a Nordic Semiconductor nRF24L01+ 2.4 GHz transceiver module used in low-power wireless sensor and IoT networks, depicted as a rectangular… |
| OLED Display Module symbol | The OLED Display Module symbol represents an SSD1306-based 0.96-inch 128×64-pixel monochrome OLED (organic light-emitting diode) display module communicating with a host microcont… |
| Op-Amp (DIP) symbol | The Op-Amp (DIP) symbol represents an operational amplifier packaged in a Dual In-line Package (DIP), drawn as a right-pointing triangle with the non-inverting input (In+) at the… |
| Optocoupler Module symbol | The Optocoupler Module symbol represents a PCB breakout module — incorporating a PC817 or 4N35 optocoupler IC, a current-limiting resistor, and screw-terminal or header connectors… |
| P-Channel MOSFET symbol | The P-Channel MOSFET symbol represents a P-channel enhancement-mode (or depletion-mode) Metal-Oxide-Semiconductor Field-Effect Transistor, designated Q in schematics, that conduct… |
| Photodiode symbol | The Photodiode symbol represents a light-sensitive semiconductor diode with Anode and Cathode terminals, drawn per IEC 60617 as the standard diode triangle-and-bar with two small… |
| Photoresistor (LDR) symbol | The Photoresistor (LDR) symbol represents a two-terminal passive resistor whose resistance decreases as incident light intensity increases, drawn in schematics as the standard res… |
| Phototransistor symbol | The Phototransistor symbol represents a bipolar transistor whose base current is generated by incident light rather than an electrical connection, drawn per IEC 60617 as an NPN tr… |
| Piezo Buzzer symbol | The Piezo Buzzer symbol represents an electromechanical sound-emitting device, designated BZ or LS in schematics, that converts electrical energy into audible sound using the piez… |
| PIR Motion Sensor symbol | The PIR Motion Sensor symbol represents a passive infrared detection module, commonly the HC-SR501 or equivalent, that detects movement within its field of view by sensing changes… |
| PN532 NFC Module symbol | The PN532 NFC Module symbol represents a near-field communication and RFID transceiver module based on the NXP PN532 chip, depicted in schematic diagrams as a labelled rectangular… |
| PNP Transistor (BJT) symbol | The PNP Transistor (BJT) symbol represents a bipolar junction transistor with a p-type emitter, n-type base, and p-type collector, defined in IEC 60617-05 and ANSI Y32.2 / IEEE 31… |
| Portable Power Bank symbol | The Portable Power Bank symbol represents a rechargeable lithium-ion battery pack with a built-in USB charge controller, depicted in circuit and system diagrams as a labelled rect… |
| Potentiometer symbol | The Potentiometer symbol represents a three-terminal variable resistor whose output voltage or resistance is set by rotating or sliding a wiper contact along a resistive element,… |
| Push Button symbol | The Push Button symbol represents a momentary-action switch with two terminals (A and B) that closes its contacts only while pressed and returns to its open (rest) state when rele… |
| Raspberry Pi symbol | The Raspberry Pi symbol represents the Raspberry Pi single-board computer (SBC) in schematic and wiring diagrams, depicted as a rectangle labelled 'Raspberry Pi' with GPIO pins (G… |
| Reed Switch symbol | The Reed Switch symbol represents a magnetically operated, hermetically sealed contact with two terminals (A, B), drawn per IEC 60617 as a switch contact enclosed in an elongated… |
| Relay Module symbol | The Relay Module symbol represents a single-channel electromechanical relay on a breakout PCB, depicted in circuit diagrams with a Coil + and Coil − control input and three SPDT l… |
| Relay SPDT symbol | The Relay SPDT symbol represents a Single-Pole Double-Throw electromagnetic relay — defined in IEC 60617-07 and ANSI Y32.2 / IEEE 315 — a five-terminal switching device with a coi… |
| Resistor symbol | The Resistor symbol represents a passive two-terminal component that opposes the flow of electric current, drawn as a zigzag line in ANSI Y32.2 / IEEE 315-1975 or as a plain recta… |
| RFID RC522 Module symbol | The RFID RC522 Module symbol represents a 13.56 MHz MFRC522-based Radio Frequency Identification reader/writer module — interfaced via SPI bus — depicted in circuit diagrams with… |
| RGB LED (4-pin) symbol | The RGB LED (4-pin) symbol represents a four-terminal Light Emitting Diode package containing three separate LED dies — Red (R), Green (G), and Blue (B) — sharing a Common anode o… |
| Rotary Encoder symbol | The Rotary Encoder symbol represents an electromechanical position-sensing device that converts angular shaft rotation into a digital pulse-train output, depicted as a rectangular… |
| Rotary Encoder Module symbol | The Rotary Encoder Module symbol represents a mechanical incremental rotary encoder board (commonly the KY-040 module) that outputs two quadrature digital pulse trains (CLK and DT… |
| Rotary Switch symbol | The Rotary Switch symbol represents a multi-position selector in which a rotating wiper connects one Common terminal to one of several selectable contacts (here Pos 1 through Pos… |
| RTC DS3231 Module symbol | The RTC DS3231 Module symbol represents a real-time clock module built around the Maxim DS3231 temperature-compensated crystal oscillator (TCXO) IC, depicted as a rectangular bloc… |
| Schottky Diode symbol | The Schottky Diode symbol represents a metal-semiconductor junction diode with a lower forward voltage drop (typically 0.15–0.45 V) and faster reverse recovery than a standard p-n… |
| Screw Terminal (2-pos) symbol | The Screw Terminal (2-pos) symbol represents a 2-position screw-clamp connector used in circuit diagrams to denote a mechanical connection point where two conductors are secured w… |
| Screw Terminal (3-pos) symbol | The Screw Terminal (3-pos) symbol represents a 3-position screw-clamp connector in circuit and wiring diagrams, denoting a three-conductor mechanical connection block where each c… |
| SD Card Module symbol | The SD Card Module symbol represents a microSD/SD card interface breakout module in electronic schematic diagrams, denoting a board-level device that adapts an SD or microSD flash… |
| Servo Motor symbol | The Servo Motor symbol represents a closed-loop actuator that uses pulse-width modulation (PWM) position commands to drive a DC motor with internal gear reduction and feedback pot… |
| Seven-Segment Display symbol | The Seven-Segment Display symbol represents a numeric LED (or LCD) display module consisting of seven independently controllable bar-shaped segments arranged to form any decimal d… |
| Shift Register (8-bit) symbol | The Shift Register (8-bit) symbol represents a serial-in/parallel-out (SIPO) digital storage register that accepts data serially on a single DATA pin, shifts it through eight inte… |
| Slide Switch symbol | The Slide Switch symbol represents a maintained-contact SPDT (single-pole double-throw) switch in which a sliding actuator physically moves a contact blade between two positions,… |
| Solar Cell (Small) symbol | The Solar Cell (Small) symbol represents a single photovoltaic cell drawn as a labeled rectangle with a 'PV' designation and two output terminals (+ and −), denoting a semiconduct… |
| Solenoid Coil symbol | The Solenoid Coil symbol represents an electromagnetic actuator coil that converts current into linear mechanical motion of a ferromagnetic plunger, drawn per IEC 60617 as a serie… |
| Speaker symbol | The Speaker symbol represents an electro-acoustic transducer drawn as a rectangular voice-coil body connected to a triangular cone (diaphragm) with two radiation-arc lines indicat… |
| Stepper Motor symbol | The Stepper Motor symbol represents a digital-pulse-driven electromechanical actuator drawn as a circle labeled 'M / STEP' with three coil-winding input pins (A1, A2, B1) and one… |
| Supercapacitor symbol | The Supercapacitor symbol represents an electric double-layer capacitor (EDLC) — a polarised energy-storage device that stores charge electrostatically at the electrode–electrolyt… |
| TCS3200 Color Sensor symbol | The TCS3200 Color Sensor symbol represents an integrated colour-to-frequency converter IC — manufactured by ams-OSRAM (formerly Texas Advanced Optoelectronic Solutions) — that ill… |
| TFT LCD Display symbol | The TFT LCD Display symbol represents a Thin-Film Transistor Liquid Crystal Display module — an active-matrix colour display interfaced via SPI or parallel bus — used in circuit d… |
| Thermistor (NTC) symbol | The Thermistor (NTC) symbol represents a thermally-sensitive resistor whose resistance decreases as temperature rises (Negative Temperature Coefficient), drawn in circuit diagrams… |
| Trimpot / Trimmer symbol | The Trimpot / Trimmer symbol represents a miniature, board-mounted variable resistor used for one-time or infrequent circuit calibration, standardised under IEC 60617-04 and ANSI… |
| Ultrasonic Sensor symbol | The Ultrasonic Sensor symbol represents a module that measures distance by emitting a 40 kHz ultrasonic pulse via a TRIG signal and timing the echo return on the ECHO pin, commonl… |
| USB Connector symbol | The USB Connector symbol represents a Universal Serial Bus interface connector used for data communication and power delivery between electronic devices, standardised in USB speci… |
| Variable Resistor symbol | The Variable Resistor symbol represents a two-terminal passive component whose resistance can be adjusted continuously between zero and its maximum rated value, standardised in IE… |
| Varistor (MOV) symbol | The Varistor (MOV) symbol represents a voltage-dependent, nonlinear resistor — most commonly a Metal Oxide Varistor (MOV) — defined in IEC 60617 and recognised in ANSI Y32.2 / IEE… |
| Voltage Divider Module symbol | The Voltage Divider Module symbol represents a pre-built resistor-based scaling module with a three-terminal interface (VIN, GND, VOUT), used in circuit diagrams to indicate a pac… |
| Voltage Regulator symbol | The Voltage Regulator symbol represents a three-terminal linear or switching power-regulation block, standardised in schematic practice under ANSI Y32.2 / IEEE 315 conventions, th… |
| Wemos D1 Mini symbol | The Wemos D1 Mini symbol represents a compact ESP8266-based Wi-Fi development module in circuit and schematic diagrams, denoting an Arduino-compatible microcontroller board with a… |
| WS2812 Addressable LED symbol | The WS2812 Addressable LED symbol represents a self-contained RGB LED module with an integrated control IC, commonly known by the trade name NeoPixel, that receives a single-wire… |
| Zener Diode symbol | The Zener Diode symbol represents a two-terminal semiconductor device that conducts normally in the forward direction but also conducts in reverse at a precise, stable breakdown v… |
Professional & Analog/Digital symbols
| Symbol | Meaning |
|---|---|
| 4-Bit Counter symbol | The 4-Bit Counter symbol represents a synchronous digital integrated circuit that increments (or decrements) a 4-bit binary value by one on each active clock edge, producing outpu… |
| 7-Segment Decoder symbol | The 7-Segment Decoder symbol represents a combinational logic integrated circuit that converts a 4-bit BCD (Binary Coded Decimal) or binary input (pins A, B, C, D) into seven segm… |
| ADC Block symbol | The ADC Block symbol represents an Analog-to-Digital Converter functional block in circuit and system diagrams, denoting a circuit element that samples a continuous analog input v… |
| Amplifier Block symbol | The Amplifier Block symbol represents a generic signal amplification stage in circuit and system block diagrams, denoting a functional element that increases the power, voltage, o… |
| AND Gate symbol | The AND Gate symbol represents a two-input (or more) combinational logic gate whose output is HIGH (logic 1) only when all inputs are simultaneously HIGH, drawn as a D-shaped curv… |
| Antenna symbol | The Antenna symbol represents a transducer that converts between guided electromagnetic waves (in a transmission line) and free-space radio waves, drawn in IEC 60617-07 as a verti… |
| Astable Multivibrator symbol | The Astable Multivibrator symbol represents a free-running oscillator circuit that continuously switches between two unstable states, generating a periodic square-wave output with… |
| Balun symbol | The Balun symbol represents a transformer-based or transmission-line device that converts between a balanced signal (two conductors carrying equal and opposite signals relative to… |
| Bandpass Filter Block symbol | The Bandpass Filter Block symbol represents a two-port frequency-selective network that passes signals within a defined passband (between lower cutoff frequency f_L and upper cuto… |
| Bandstop Filter Block symbol | The Bandstop Filter Block symbol represents a two-port frequency-selective network that attenuates signals within a defined stop band (between lower cutoff frequency f_L and upper… |
| BCD Counter symbol | The BCD Counter symbol represents a digital integrated circuit that counts input clock pulses and outputs the count in 4-bit Binary Coded Decimal (BCD) format, cycling from 0000 (… |
| Boost Converter (Topology) symbol | The Boost Converter (Topology) symbol represents the fundamental switched-mode power supply circuit topology that steps a DC input voltage up to a higher DC output voltage using a… |
| Buck Converter (Topology) symbol | The Buck Converter (Topology) symbol represents the fundamental switched-mode power supply circuit topology that reduces a DC input voltage to a lower DC output voltage using a sw… |
| Buffer symbol | The Buffer symbol represents a non-inverting digital logic gate that reproduces its input signal at its output without logical inversion, providing signal amplification and electr… |
| CCCS (Dependent Current Source) symbol | The CCCS symbol represents a current-controlled current source — a dependent source whose output current equals a dimensionless current gain β (A/A) times a controlling current fl… |
| CCVS (Dependent Voltage Source) symbol | The CCVS symbol represents a current-controlled voltage source — a dependent source whose output voltage equals a transresistance rm (in ohms, volts per amp) times a controlling c… |
| Center-Tap Transformer symbol | The Center-Tap Transformer symbol represents a transformer whose secondary winding has an additional connection brought out at its electrical midpoint, splitting the secondary int… |
| Charge Pump symbol | The Charge Pump symbol represents a switched-capacitor DC-DC converter block — used in power electronics schematics — that uses capacitors as energy-transfer elements switched by… |
| Clamper Circuit symbol | The Clamper Circuit symbol represents an electronic signal-conditioning block — also known as a DC restorer — that shifts the entire waveform of an AC or pulsed signal up or down… |
| Colpitts Oscillator symbol | The Colpitts Oscillator symbol represents an LC feedback oscillator circuit block — named after Edwin Colpitts who patented it in 1918 — that generates a sinusoidal output frequen… |
| Comparator symbol | The Comparator symbol represents an analog circuit element — drawn as a triangle (op-amp outline) with a non-inverting input (In+), an inverting input (In−), and a single digital-… |
| Crystal Oscillator Module symbol | The Crystal Oscillator Module symbol represents a complete pre-packaged clock source — drawn as a rectangular IC block with VCC, GND, and CLK output pins (and optionally an enable… |
| Current Mirror symbol | The Current Mirror symbol represents a two-terminal active circuit block — drawn as a rectangular functional block with a reference current input (I_ref) and a mirrored current ou… |
| Current Source symbol | The Current Source symbol represents an ideal two-terminal circuit element that forces a constant or controlled current through a circuit regardless of the voltage across its term… |
| D Flip-Flop symbol | The D Flip-Flop symbol represents an edge-triggered bistable storage element that captures the logic level present at its Data input (D) on the active clock edge and holds that va… |
| DAC Block symbol | The DAC Block symbol represents a Digital-to-Analogue Converter, a circuit element that translates an n-bit binary digital input word into a proportional continuous analogue outpu… |
| Darlington Pair symbol | The Darlington Pair symbol represents a compound transistor configuration in which two bipolar junction transistors (BJTs) are connected so that the emitter of the first transisto… |
| Decoder (3:8) symbol | The Decoder (3:8) symbol represents a combinational logic functional block that decodes a 3-bit binary input address into one of eight unique active output lines, activating exact… |
| Demultiplexer (DEMUX) symbol | The Demultiplexer (DEMUX) symbol represents a combinational logic functional block that routes a single data input to one of several outputs selected by binary address inputs, act… |
| DIAC symbol | The DIAC symbol represents a bidirectional two-terminal thyristor that conducts current in either direction once the applied voltage exceeds its breakover voltage (V_BO), used pri… |
| Differential Amplifier symbol | The Differential Amplifier symbol represents an analogue circuit block that amplifies the voltage difference between its non-inverting input (IN+) and inverting input (IN−) while… |
| Differentiator symbol | The Differentiator symbol represents an analogue op-amp circuit block whose output voltage is proportional to the rate of change (time derivative) of its input voltage—V_out = −RC… |
| Digital Comparator symbol | The Digital Comparator symbol represents a combinational logic functional block that compares two multi-bit binary numbers (A and B) and asserts one of three mutually exclusive ou… |
| Directional Coupler symbol | The Directional Coupler symbol represents a passive four-port RF and microwave network component that samples a small, fixed fraction of the signal power travelling in one directi… |
| Emitter Follower symbol | The Emitter Follower symbol represents a common-collector bipolar junction transistor (BJT) amplifier stage in which the output is taken from the emitter terminal, providing unity… |
| Encoder (Priority) symbol | The Encoder (Priority) symbol represents a combinational logic block that converts 2^n input lines into an n-bit binary code output, with priority encoding ensuring the highest-nu… |
| Envelope Detector symbol | The Envelope Detector symbol represents an analogue signal-processing block that extracts the slowly-varying amplitude envelope from a high-frequency amplitude-modulated (AM) carr… |
| Flyback Converter symbol | The Flyback Converter symbol represents an isolated DC-DC switching power supply topology that uses a coupled inductor (flyback transformer) to transfer energy from primary to sec… |
| FPGA Block symbol | The FPGA Block symbol represents a Field-Programmable Gate Array integrated circuit — a reconfigurable logic device whose internal interconnect and logic functions are defined by… |
| Frequency Divider symbol | The Frequency Divider symbol represents a digital circuit block that outputs a clock signal whose frequency is an integer fraction (1/N) of the input clock frequency, shown in blo… |
| FSK Modulator symbol | The FSK Modulator symbol represents a digital modulation block that encodes binary data by shifting a carrier frequency between two discrete values (mark and space frequencies) co… |
| Full-Wave Rectifier symbol | The Full-Wave Rectifier symbol represents a four-diode bridge circuit that converts both half-cycles of an AC input into a unidirectional pulsating DC output, shown in schematics… |
| Gate Driver symbol | The Gate Driver symbol represents a dedicated integrated circuit that amplifies a low-power logic control signal into the high-current drive waveform required to rapidly charge an… |
| Gilbert Cell Mixer symbol | The Gilbert Cell Mixer symbol represents a doubly-balanced active analog multiplier circuit — typically built from a differential transistor quad and a tail current source — used… |
| Ground (Chassis) symbol | The Ground (Chassis) symbol represents a connection point tied to the conductive enclosure or mechanical frame of equipment — not necessarily connected to Earth ground — used in s… |
| Ground (Signal) symbol | The Ground (Signal) symbol represents the internal circuit voltage reference — commonly called common ground, analog ground, or signal common — at 0 V relative to which all signal… |
| H-Bridge symbol | The H-Bridge symbol represents a four-switch power topology — named for its H-shaped circuit arrangement of four transistors (or MOSFETs) bridging a DC motor or load between the s… |
| Half-Wave Rectifier symbol | The Half-Wave Rectifier symbol represents a two-terminal circuit block containing a single diode that converts alternating current (AC) to pulsating direct current (DC) by conduct… |
| Highpass Filter Block symbol | The Highpass Filter Block symbol represents a two-terminal frequency-selective network that passes signals above its cutoff frequency (f_c) while attenuating signals below f_c, de… |
| IGBT symbol | The IGBT (Insulated Gate Bipolar Transistor) symbol represents a three-terminal voltage-controlled power switching device that combines the high-input-impedance gate drive of a MO… |
| Instrumentation Amplifier symbol | The Instrumentation Amplifier symbol represents a precision differential-input amplifier with high common-mode rejection ratio (CMRR), very high input impedance, and a single exte… |
| Integrator symbol | The Integrator symbol represents an analog signal-processing circuit — typically an op-amp with a capacitor in the feedback path — that produces an output voltage proportional to… |
| JK Flip-Flop symbol | The JK Flip-Flop symbol represents a clocked bistable sequential logic element in circuit diagrams, drawn as a rectangular block with inputs J, CLK, and K on the left and outputs… |
| Linear Regulator Block symbol | The Linear Regulator Block symbol represents a three-terminal voltage-regulation circuit or IC that maintains a fixed or adjustable DC output voltage (VOUT) by dissipating excess… |
| Log Amplifier symbol | The Log Amplifier symbol represents an analogue circuit block whose output voltage is proportional to the logarithm of its input voltage or current, used in circuit diagrams to in… |
| Low Noise Amplifier symbol | The Low Noise Amplifier (LNA) symbol represents a two-port active amplifier block placed at the input of a receiver chain that provides signal gain with the minimum possible added… |
| Lowpass Filter Block symbol | The Lowpass Filter Block symbol represents a two-terminal analogue or digital signal-processing element that passes frequencies below a defined cutoff frequency (f_c) while attenu… |
| Monostable Multivibrator symbol | The Monostable Multivibrator symbol represents a single-output pulse-generating circuit block — also called a one-shot timer — that produces one fixed-width output pulse for each… |
| Multiplexer (MUX) symbol | The Multiplexer (MUX) symbol represents a digital or analog combinational logic circuit that selects one of multiple input signals (I0, I1, I2) and routes it to a single output (O… |
| Multiplexer 4:1 symbol | The Multiplexer 4:1 symbol represents a four-input, one-output digital data selector circuit — commonly implemented by the 74HC153 — that connects one of four data inputs (I0, I1,… |
| N-Channel JFET symbol | The N-Channel JFET symbol represents a junction field-effect transistor whose N-type conductive channel between Drain and Source is narrowed by reverse-biasing the P-type Gate jun… |
| NAND Gate symbol | The NAND Gate symbol represents a universal logic gate that produces a LOW (0) output only when all of its inputs (A and B) are simultaneously HIGH (1), and a HIGH (1) output for… |
| Noise Source symbol | The Noise Source symbol represents an idealized or physical circuit element that generates a specified broadband random noise signal — such as white noise, thermal (Johnson–Nyquis… |
| NOR Gate symbol | The NOR Gate symbol represents a digital logic gate whose output is LOW (logic 0) whenever any one or more of its inputs are HIGH (logic 1), and HIGH (logic 0) only when all input… |
| NOT Gate / Inverter symbol | The NOT Gate / Inverter symbol represents a single-input, single-output digital logic gate whose output is always the logical complement of its input — HIGH when the input is LOW… |
| NPN Transistor symbol | The NPN Transistor symbol represents an NPN bipolar junction transistor (BJT) — drawn as a circle (device envelope) containing a vertical base bar with a line from the Base termin… |
| Op-Amp symbol | The Op-Amp symbol represents an operational amplifier — a high-gain, differential-input voltage amplifier — defined in IEC 60617-05 and ANSI Y32.2 / IEEE 315 as a triangle pointin… |
| Optocoupler symbol | The Optocoupler symbol represents an optoelectronic isolation device — standardised in IEC 60747-5 and depicted per IEC 60617 and ANSI Y32.2/IEEE 315 — that transmits signals betw… |
| OR Gate symbol | The OR Gate symbol represents a digital logic gate — standardised in IEC 60617-12 and ANSI Y32.2/IEEE 315 — whose output is logic HIGH (1) whenever one or more of its inputs (A or… |
| P-Channel JFET symbol | The P-Channel JFET symbol represents a junction field-effect transistor whose P-type conductive channel between Drain and Source is narrowed by reverse-biasing the N-type Gate jun… |
| Peak Detector symbol | The Peak Detector symbol represents an analog signal-processing circuit block — built around an operational amplifier (op-amp), diode, and hold capacitor — that captures and holds… |
| Phase Detector symbol | The Phase Detector symbol represents an analog or digital circuit block — a key sub-component of a Phase-Locked Loop (PLL) — that compares the phase (and optionally frequency) of… |
| Pi Attenuator symbol | The Pi Attenuator symbol represents a passive resistive network in a π (pi) topology — one series resistor between input and output with two shunt resistors to ground — used in RF… |
| PLL Block symbol | The PLL Block symbol represents a Phase-Locked Loop — a closed-loop feedback circuit used in electronic and RF schematics to denote a system that locks the frequency and phase of… |
| Power Amplifier Block symbol | The Power Amplifier Block symbol represents a high-power signal-amplification stage in a circuit diagram, depicted per IEC 60617 and IEEE 315-1975 conventions as a triangle or rec… |
| Precision Rectifier symbol | The Precision Rectifier symbol represents an op-amp-based circuit that rectifies AC signals to DC with near-zero forward-voltage drop, overcoming the 0.6 V diode threshold that li… |
| Precision Voltage Reference symbol | The Precision Voltage Reference symbol represents a two- or three-terminal active circuit element used in schematics to denote a device that produces a stable, temperature-compens… |
| PTAT Current Source symbol | The PTAT Current Source symbol represents a Proportional To Absolute Temperature current source — an analog circuit block whose output current increases linearly with absolute tem… |
| RAM Block symbol | The RAM Block symbol represents a Random Access Memory module or functional block in digital circuit schematics, depicted as a rectangle labelled 'RAM' with address (ADDR), write-… |
| RF Attenuator symbol | The RF Attenuator symbol represents a passive two-port network — labelled ATT or −x dB in circuit diagrams and RF schematics — that reduces the power level of a radio-frequency si… |
| RF Log Detector symbol | The RF Log Detector symbol represents an integrated circuit block that converts RF or IF signal power into a DC output voltage proportional to the logarithm of the input power, pr… |
| RF Mixer symbol | The RF Mixer symbol represents a three-port non-linear circuit element — depicted as a circle with an X (multiplication symbol) in RF and microwave schematics — that combines an R… |
| Sample and Hold symbol | The Sample and Hold symbol represents an analog circuit that captures (samples) the instantaneous value of an input voltage on command and retains (holds) that voltage at its outp… |
| SAR ADC symbol | The SAR ADC symbol represents a Successive Approximation Register analog-to-digital converter that converts an analog input voltage to an n-bit digital code by iteratively compari… |
| Schmitt Trigger symbol | The Schmitt Trigger symbol represents an analog or digital circuit element with two distinct input switching thresholds — a positive-going threshold (VT+) and a negative-going thr… |
| Schmitt Trigger NAND symbol | The Schmitt Trigger NAND symbol represents a two-input NAND logic gate with integrated Schmitt trigger hysteresis on each input, depicted as a standard NAND gate shape with input… |
| Sigma-Delta ADC symbol | The Sigma-Delta ADC symbol represents a high-resolution analogue-to-digital converter that uses oversampling and noise-shaping techniques to achieve 16-bit to 32-bit resolution at… |
| Signal Generator symbol | The Signal Generator symbol represents a test-equipment source that produces a defined periodic waveform — sine, square, triangle, or arbitrary — at a settable frequency and ampli… |
| Signal Limiter symbol | The Signal Limiter symbol represents a two-terminal active or passive circuit block that clips or clamps an input signal's amplitude to a defined maximum and/or minimum level, all… |
| Snubber Network symbol | The Snubber Network symbol represents a passive RC (resistor-capacitor) or RCD circuit placed in parallel with a switching element or inductive load in a schematic diagram, used p… |
| Squelch Circuit symbol | The Squelch Circuit symbol represents a noise-gating signal-processing block drawn as a labeled rectangle with an audio/RF input (In), a threshold control input (Thrs), and a gate… |
| SR Latch symbol | The SR Latch symbol represents a basic bistable sequential logic element drawn as a labeled rectangle with Set (S) and Reset (R) inputs and complementary outputs Q and Q̄ (Q-bar),… |
| Summing Amplifier symbol | The Summing Amplifier symbol represents an operational-amplifier circuit configured with multiple inverting inputs through individual input resistors to a single virtual-ground su… |
| T Attenuator symbol | The T Attenuator symbol represents a passive resistive network in a T (tee) topology — two series resistors between input and output with one shunt resistor to ground at the midpo… |
| T Flip-Flop symbol | The T Flip-Flop symbol represents a Toggle flip-flop — a clocked sequential logic element that changes (toggles) its output state on every active clock edge when the T (Toggle) in… |
| Test Point symbol | The Test Point symbol represents a dedicated accessible node in a circuit — typically a small solder pad, via, or probe connector on a PCB — that provides a defined measurement lo… |
| Thyristor / SCR symbol | The Thyristor / SCR symbol represents a silicon controlled rectifier — a four-layer (PNPN) power semiconductor device that acts as a bistable switch conducting from anode to catho… |
| Transformer symbol | The Transformer symbol represents a passive electromagnetic device — drawn as two sets of coil loops (or semi-circles) facing each other, separated by one or two vertical lines re… |
| Transimpedance Amplifier symbol | The Transimpedance Amplifier symbol represents a current-to-voltage converter circuit—drawn as a standard op-amp triangle symbol with a feedback resistor (and optionally feedback… |
| Tri-State Buffer symbol | The Tri-State Buffer symbol represents a digital logic gate that drives its output to logic HIGH, logic LOW, or a high-impedance (Hi-Z) floating state under control of an Enable (… |
| TRIAC symbol | The TRIAC symbol represents a bidirectional, gate-triggered thyristor used in AC power-control circuits, standardised under IEC 60617 and ANSI Y32.2 / IEEE 315, with three termina… |
| Varactor Diode symbol | The Varactor Diode symbol represents a PN-junction diode operated in reverse bias as a voltage-variable capacitor — its junction capacitance falls as reverse voltage rises — drawn… |
| VCCS (Dependent Current Source) symbol | The VCCS symbol represents a voltage-controlled current source — a dependent source whose output current equals a transconductance gm (in siemens, amps per volt) times a controlli… |
| VCO Block symbol | The VCO Block symbol represents a Voltage-Controlled Oscillator functional block with a control voltage input (CTRL) and a signal output (OUT), defined in schematic practice under… |
| VCVS (Dependent Voltage Source) symbol | The VCVS symbol represents a voltage-controlled voltage source — a dependent source whose output voltage equals a dimensionless gain μ (V/V) times a controlling voltage measured e… |
| VGA DAC Block symbol | The VGA DAC Block symbol represents a digital-to-analog converter stage used in circuit diagrams to depict the interface circuit that converts digital RGB pixel data into the thre… |
| Voltage Divider symbol | The Voltage Divider symbol represents two resistors connected in series between an input voltage (Vin) and ground, with the output voltage (Vout) tapped at the midpoint junction b… |
| Voltage Doubler symbol | The Voltage Doubler symbol represents a switched-capacitor or diode-capacitor charge-pump circuit block with two input terminals (In+ and In-) and two output terminals (Out+ and O… |
| Voltage Source (AC) symbol | The Voltage Source (AC) symbol represents an ideal two-terminal source of sinusoidal alternating voltage, defined in IEC 60617-02 as a circle enclosing a sine wave symbol, and in… |
| Voltage Source (DC) symbol | The Voltage Source (DC) symbol represents an ideal two-terminal source of constant direct voltage, defined in IEC 60617-02 as a circle with a long line (positive terminal) and a s… |
| Wheatstone Bridge symbol | The Wheatstone Bridge symbol represents a four-resistor diamond-shaped measurement circuit used in schematic diagrams to denote a balanced bridge configuration that determines an… |
| Wien Bridge Oscillator symbol | The Wien Bridge Oscillator symbol represents a low-distortion RC sinusoidal oscillator circuit used in schematic diagrams to denote a signal source that generates a stable sine wa… |
| XNOR Gate symbol | The XNOR Gate symbol represents a digital logic gate whose output is logic HIGH (1) when all inputs are equal (both 0 or both 1) and logic LOW (0) when inputs differ, making it th… |
| XOR Gate symbol | The XOR Gate symbol represents a digital logic gate whose output is logic HIGH (1) when its inputs differ (one is HIGH and the other is LOW) and logic LOW (0) when all inputs are… |
| Zero-Crossing Detector symbol | The Zero-Crossing Detector symbol represents an analogue or mixed-signal circuit block that produces a narrow digital pulse output each time its AC input signal crosses through ze… |
Industrial & Control symbols
| Symbol | Meaning |
|---|---|
| 3-Phase Motor symbol | The 3-Phase Motor symbol represents a three-phase AC induction or synchronous motor, depicted in IEC 60617-06 as a circle containing the letter M annotated '3~', with three supply… |
| 3-Phase Plug (CEE / Industrial) symbol | The 3-Phase Plug (CEE / Industrial) symbol represents an industrial polyphase electrical connector—drawn as a circle or plug-face diagram with four or five contact positions label… |
| 3-Phase Supply symbol | The 3-Phase Supply symbol represents a three-phase alternating-current power source in electrical schematics and wiring diagrams, denoting a system with three conductors (L1, L2,… |
| 3-Pole Contactor symbol | The 3-Pole Contactor symbol represents a heavy-duty electromechanical switching device with three main power contacts (L1, L2, L3 → T1, T2, T3) operated by an electromagnetic coil… |
| 3.5mm Audio Jack (TRS) symbol | The 3.5mm Audio Jack (TRS) symbol represents a 3-conductor miniature phone connector in circuit diagrams, identified by three pins — Tip (Left channel), Ring (Right channel), and… |
| 4-Pole Contactor symbol | The 4-Pole Contactor symbol represents an electromechanical switching device with four independently-switched main contacts (L1, L2, L3, L4 → T1, T2, T3, T4) operated by a single… |
| Alternator symbol | The Alternator symbol represents an electromechanical AC generator — most commonly the automotive charging alternator — in circuit and wiring diagrams, denoting a rotating machine… |
| Ammeter symbol | The Ammeter symbol represents a current-measuring instrument inserted in series with a circuit to indicate the magnitude of electric current flowing through that branch, shown in… |
| Automotive Relay (5-pin) symbol | The Automotive Relay symbol represents the standard 12 V SPDT 'mini' (Bosch-style) relay used throughout vehicle wiring, drawn as a box containing a coil and a changeover contact… |
| Autotransformer symbol | The Autotransformer symbol represents a single-winding transformer in which part of the winding serves as both the primary and secondary, allowing voltage step-up or step-down wit… |
| Battery Charger symbol | The Battery Charger symbol represents an AC-to-DC converter that rectifies mains power and regulates it through charge stages (bulk, absorption, float, and optionally equalize) to… |
| BLDC / Brushless DC Motor symbol | The BLDC / Brushless DC Motor symbol represents a three-phase permanent-magnet synchronous motor that is electronically commutated via an inverter or ESC, shown in circuit diagram… |
| Bus Tie Switch symbol | The Bus Tie Switch symbol represents a normally-open switching device used in electrical distribution schematics to interconnect two separate bus sections (Bus A and Bus B) of a s… |
| Buzzer / Audible Alarm symbol | The Buzzer / Audible Alarm symbol represents a polarised electromechanical or piezoelectric sound-emitting device used in circuit diagrams to indicate an audible alert output, sho… |
| Cable Entry / Gland symbol | The Cable Entry / Gland symbol represents a mechanical cable entry fitting — used in wiring and installation diagrams per IEC 60617 and industrial drawing practice — that seals an… |
| Cable Lug / Crimp Terminal symbol | The Cable Lug / Crimp Terminal symbol represents a mechanical crimped or compression terminal — standardised under IEC 61238-1 and ANSI/NEMA standards — that permanently joins a s… |
| Cable Tray symbol | The Cable Tray symbol represents a continuous rigid structural system — standardised under IEC 61537 and NEMA FG1 / UL 568 — used in electrical installation drawings to show the r… |
| Capacitor Bank symbol | The Capacitor Bank symbol represents a group of capacitors connected in parallel (or series-parallel) as a single power system element — used in power engineering diagrams per IEC… |
| Changeover Contact (SPDT) symbol | The Changeover Contact (SPDT) symbol represents a single-pole double-throw relay or switch contact — standardised in IEC 60617-07 and ANSI/IEEE 315 — with one Common terminal that… |
| Check Valve symbol | The Check Valve symbol represents a one-way (non-return) valve — standardised in ISO 1219-1 for hydraulic and pneumatic circuit diagrams — that allows fluid or gas to flow in only… |
| Circuit Breaker (MCB) symbol | The Circuit Breaker (MCB) symbol represents a Miniature Circuit Breaker — drawn as a rectangle containing a diagonal trip-bar line and a switching contact, or as a simple switch-i… |
| Compressor symbol | The Compressor symbol represents the hermetic motor-compressor of a refrigeration, air-conditioning, or heat-pump system — a single-phase induction motor sealed with its pump in o… |
| Contactor Coil symbol | The Contactor Coil symbol represents the electromagnetic operating coil of a contactor or relay, drawn as a rectangle with two terminals (A1 and A2), used in control-circuit wirin… |
| Contactor NC Contact symbol | The Contactor NC Contact symbol represents a normally-closed (NC) auxiliary contact of a contactor, drawn as two terminal bars with a diagonal bridging line and a perpendicular st… |
| Contactor NO Contact symbol | The Contactor NO Contact symbol represents a normally-open (NO) auxiliary contact of a contactor, drawn as two terminal bars with an open gap and a diagonal bridging line showing… |
| Current Limiting Reactor symbol | The Current Limiting Reactor symbol represents a series air-core or iron-core inductor — drawn as a series of loops or arcs (ANSI zigzag/coil) or as a rectangle (IEC) with two ter… |
| Current Transformer (CT) symbol | The Current Transformer (CT) symbol represents an instrument transformer that produces a secondary current proportional to the primary current flowing through its core, used for m… |
| DIN Rail symbol | The DIN Rail symbol represents the standardised metal mounting track—defined in IEC 60715 as the TS 35 (top-hat) profile measuring 35 mm wide—used in electrical control panels, di… |
| DIN Rail End Stop symbol | The DIN Rail End Stop symbol represents a mechanical end-bracket accessory mounted on a DIN rail (TS 35 / EN 60715) to prevent terminal blocks, circuit breakers, and other rail-mo… |
| Disconnect Switch / Isolator symbol | The Disconnect Switch / Isolator symbol represents a manually operated switching device in industrial electrical schematics that provides positive, visible isolation of a circuit… |
| Distributed I/O Module symbol | The Distributed I/O Module symbol represents a remote input/output device in industrial automation schematics that connects field sensors and actuators to a central PLC or DCS ove… |
| Door Interlock Switch symbol | The Door Interlock Switch symbol represents a safety switching device in electrical and control system diagrams that monitors the open/closed state of an enclosure door, guard, or… |
| Earth Leakage Relay symbol | The Earth Leakage Relay symbol represents a protective relay that monitors residual ground-fault current in an electrical installation and issues a trip signal when leakage curren… |
| Emergency Stop symbol | The Emergency Stop symbol represents a safety-rated manually-actuated electromechanical device that immediately interrupts power or control circuits to halt a machine in a dangero… |
| Energy Meter (kWh) symbol | The Energy Meter (kWh) symbol represents a revenue-grade electrical energy measurement device that accumulates consumed active energy in kilowatt-hours (kWh), as defined in IEC 62… |
| Fire Alarm Panel symbol | The Fire Alarm Panel symbol represents the fire alarm control unit (FACP/FACU) at the heart of a building's fire detection system, drawn as a rectangle labelled 'FACP' with termin… |
| Float Switch symbol | The Float Switch symbol represents a level-sensing switch whose contacts open or close based on liquid surface height, standardised under IEC 60617 as a mechanically-actuated swit… |
| Flow Control Valve symbol | The Flow Control Valve symbol represents a variable-restriction valve that regulates the volumetric flow rate of fluid or gas in a pipeline, shown in schematic and P&ID diagrams a… |
| Flow Switch symbol | The Flow Switch symbol represents a pilot device whose contacts change state when fluid flow in a pipe or duct exceeds (or falls below) a set point, drawn per NEMA ICS / IEC 60947… |
| Fluorescent / HID Ballast symbol | The Fluorescent / HID Ballast symbol represents a current-limiting and arc-stabilising control device for gas-discharge lamps in circuit diagrams, drawn as a labeled rectangular b… |
| Foot Switch symbol | The Foot Switch symbol represents a foot-operated pilot device that opens or closes contacts when the operator presses a pedal, drawn per NEMA ICS / IEC 60947-5-1 conventions as a… |
| Fuse symbol | The Fuse symbol represents a single-use overcurrent protection device containing a fusible element that melts and permanently opens the circuit when current exceeds the rated valu… |
| Fuse Terminal Block symbol | The Fuse Terminal Block symbol represents a modular DIN-rail-mounted terminal block with an integrated replaceable fuse element, providing both circuit connection and overcurrent… |
| Ground / Earth symbol | The Ground / Earth symbol represents a reference node connected to the Earth via a grounding electrode — providing a zero-volt potential reference and a fault-current return path… |
| Grounding Switch symbol | The Grounding Switch symbol represents a mechanically-operated isolating switch used in high-voltage and industrial electrical systems to connect a de-energised line conductor to… |
| Guitar Output Jack (TS) symbol | The Guitar Output Jack (TS) symbol represents a mono 1/4-inch (6.35 mm) TS (Tip-Sleeve) phone jack connector — the standard output socket on electric guitars and basses — used in… |
| Guitar Pickup symbol | The Guitar Pickup symbol represents an electromagnetic transducer, used in electric guitar and bass circuits, that converts string vibration into an electrical signal by means of… |
| Harmonic Filter symbol | The Harmonic Filter symbol represents a power-quality conditioning device — either passive (LC tuned circuits) or active (PWM power electronics) — installed in AC power systems to… |
| Heating Cable / Heat Trace symbol | The Heating Cable / Heat Trace symbol represents a self-regulating or constant-wattage resistive cable installed along pipes, roofs, or floors that converts electrical energy to h… |
| Heating Element symbol | The Heating Element symbol represents a resistive load that converts electrical energy directly into heat by Joule heating (P = V²/R), drawn per IEC 60617 as a rectangle (the resi… |
| HMI Touchscreen Panel symbol | The HMI Touchscreen Panel symbol represents a human-machine interface display unit — a touchscreen or keypad-based operator terminal connected to a PLC, controller, or SCADA syste… |
| Horn / Siren symbol | The Horn / Siren symbol represents an electromechanical or electronic audible-signalling device — a horn, siren, or annunciator — that produces a loud audible alert when energised… |
| Hydraulic Cylinder symbol | The Hydraulic Cylinder symbol represents a linear actuator that converts hydraulic pressure into straight-line force and motion, drawn per ISO 1219-1 as a long rectangle (the barr… |
| Hydraulic Motor symbol | The Hydraulic Motor symbol represents the rotary actuator that converts hydraulic fluid power back into mechanical shaft power, drawn per ISO 1219-1 as a circle with a filled (sol… |
| Hydraulic Pump symbol | The Hydraulic Pump symbol represents the component that converts mechanical shaft power into hydraulic fluid power, drawn per ISO 1219-1 as a circle with a filled (solid black) tr… |
| Hydraulic Reservoir symbol | The Hydraulic Reservoir symbol represents the vented tank that stores the system's fluid and performs conditioning duties — heat dissipation, air release, and contaminant settling… |
| Ignition Coil symbol | The Ignition Coil symbol represents an automotive inductive transformer that steps up a 12 V DC battery supply to a high-tension (HT) spark voltage of 15–45 kV required to ignite… |
| Ignition Switch (Multi-Position) symbol | The Ignition Switch (Multi-Position) symbol represents a key-operated rotary switch in an automotive or small-engine electrical system that sequentially connects the battery suppl… |
| Industrial Network Switch symbol | The Industrial Network Switch symbol represents a managed or unmanaged Ethernet switch used in industrial automation and control networks to interconnect PLCs, HMIs, sensors, and… |
| Inverter (DC-AC) symbol | The Inverter (DC-AC) symbol represents a power electronics device that converts direct current (DC) at its DC+ and DC− input terminals to alternating current (AC) at its AC Line (… |
| Isolation Transformer symbol | The Isolation Transformer symbol represents a transformer with a 1:1 turns ratio used in circuit diagrams to indicate galvanic isolation between two circuits, drawn as two adjacen… |
| Key Switch symbol | The Key Switch symbol represents a mechanically-operated switch that requires a physical key to actuate in circuit diagrams, drawn as a standard switch symbol (two terminals conne… |
| Knife Disconnect Switch symbol | The Knife Disconnect Switch symbol represents a manually-operated visible-blade isolating switch in circuit diagrams, drawn as a single-pole switch with a hinged blade that pivots… |
| Lightning Arrester symbol | The Lightning Arrester symbol represents a surge-protection device connected between a live conductor (Line) and earth ground that diverts high-voltage transient overvoltages caus… |
| Lightning Rod / Air Terminal symbol | The Lightning Rod / Air Terminal symbol represents a pointed metal conductor elevated above a structure to intercept lightning strikes and conduct the discharge current safely to… |
| Limit Switch NC symbol | The Limit Switch NC symbol represents a mechanically-actuated, normally-closed electrical switch that carries current in its rest (unactuated) state and opens the circuit when the… |
| Limit Switch NO symbol | The Limit Switch NO symbol represents a mechanically-actuated, normally-open electrical switch whose contacts are open (non-conducting) at rest and close to complete the circuit w… |
| Line Reactor symbol | The Line Reactor symbol represents a series-connected three-phase or single-phase inductor (choke) inserted in the AC supply or drive output line to reduce harmonic distortion, li… |
| Magneto (Engine Generator) symbol | The Magneto (Engine Generator) symbol represents a self-contained permanent-magnet alternator that generates its own ignition voltage without an external battery, used in circuit… |
| Manual Pull Station symbol | The Manual Pull Station symbol represents a manually operated fire alarm initiating device — called a manual fire alarm box in NFPA 72 and a manual call point in EN 54-11 — drawn… |
| MCCB (Molded Case CB) symbol | The MCCB (Moulded Case Circuit Breaker) symbol represents a self-contained, factory-assembled overcurrent protective device housed in a moulded insulating case, rated from 15 A to… |
| Motor Protection CB symbol | The Motor Protection CB (circuit breaker) symbol represents a combined motor protection circuit breaker — also called an MPCB or motor starter protector — that provides simultaneo… |
| Motor Protection Relay symbol | The Motor Protection Relay symbol represents an electronic or electromechanical protective relay that monitors motor current via IN+ and IN- sensing terminals and trips the motor… |
| Motor Starter (DOL) symbol | The Motor Starter (DOL) symbol represents a Direct-On-Line motor starter in industrial wiring and schematic diagrams—a control device that connects a three-phase induction motor d… |
| Multi-Level Terminal Block symbol | The Multi-Level Terminal Block symbol represents a double-deck or multi-level DIN-rail-mounted terminal block that provides two or more independent electrical connections within a… |
| NEMA L14-30 (4-prong twist-lock) symbol | The NEMA L14-30 (4-prong twist-lock) symbol represents a 30-ampere, 125/250-volt locking plug and receptacle with four terminals — X (Hot 1), Y (Hot 2), W (Neutral), and G (Ground… |
| Neutral Rail symbol | The Neutral Rail symbol represents a common return conductor bus in an AC electrical distribution system, drawn as a horizontal or vertical bar with multiple tap points labelled T… |
| OBD-II Connector (16-pin) symbol | The OBD-II Connector (16-pin) symbol represents the standardised SAE J1962 Data Link Connector (DLC) found in all passenger vehicles sold in the United States after 1996 and in Eu… |
| Overload Contact NC symbol | The Overload Contact NC symbol represents a normally-closed (NC) auxiliary contact of a thermal or electronic overload relay — standardised in IEC 60617-07 and ANSI Y32.2/IEEE 315… |
| Overload Contact NO symbol | The Overload Contact NO symbol represents a normally-open (NO) auxiliary contact of a thermal or electronic overload relay — standardised in IEC 60617-07 and ANSI Y32.2/IEEE 315 —… |
| Panel Fan symbol | The Panel Fan symbol represents a forced-ventilation cooling fan mounted inside an electrical enclosure or control panel — used in industrial and commercial panel wiring diagrams… |
| Panel Thermostat symbol | The Panel Thermostat symbol represents a temperature-sensing control device mounted inside an electrical enclosure or control panel — used in industrial wiring diagrams to indicat… |
| Phase Sequence Relay symbol | The Phase Sequence Relay symbol represents a three-phase protective device, designated K in schematics, that monitors the order (sequence) of phases L1, L2, and L3 in an AC supply… |
| Photoelectric Sensor symbol | The Photoelectric Sensor symbol represents an industrial proximity and detection device, typically designated PE or BG in schematics, that uses a modulated light beam (visible red… |
| Pilot Light / Indicator symbol | The Pilot Light / Indicator symbol represents a panel-mounted visual signalling device, designated H or HL in schematics, that illuminates to indicate the operational status — suc… |
| PLC CPU symbol | The PLC CPU symbol represents the central processing unit module of a Programmable Logic Controller, designated PLC or CPU in schematics, that executes the user's ladder logic or… |
| PLC Input Module symbol | The PLC Input Module symbol represents a digital input interface module of a Programmable Logic Controller, designated DI in schematics, that accepts discrete ON/OFF voltage signa… |
| PLC Output Module symbol | The PLC Output Module symbol represents a digital output interface module of a Programmable Logic Controller, designated DO in schematics, that receives commanded ON/OFF states fr… |
| Plug Connector Female symbol | The Plug Connector Female symbol represents a socket-type electrical connector — commonly called a receptacle or socket — used in wiring and schematic diagrams to denote the panel… |
| Plug Connector Male symbol | The Plug Connector Male symbol represents a pin-type electrical connector — commonly called a plug — used in wiring and schematic diagrams to denote the cable-end or equipment-sid… |
| Pneumatic 3/2 Valve symbol | The Pneumatic 3/2 Valve symbol represents a directional control valve with 3 ports and 2 switching positions used in compressed-air circuits to control the extension and retractio… |
| Pneumatic 5/2 Valve symbol | The Pneumatic 5/2 Valve symbol represents a directional control valve with 5 ports and 2 switching positions used in compressed-air circuits to control double-acting pneumatic cyl… |
| Pneumatic Cylinder (Double Acting) symbol | The Pneumatic Cylinder (Double Acting) symbol represents a linear actuator driven by compressed air on both the extend and retract strokes, depicted in fluid-power diagrams per IS… |
| Pneumatic Cylinder (Single Acting) symbol | The Pneumatic Cylinder (Single Acting) symbol represents a linear actuator driven by compressed air on the extend stroke only, with a spring providing the return force, depicted i… |
| Power Distribution Block symbol | The Power Distribution Block symbol represents a bus-bar or terminal assembly that accepts a single high-current input conductor and distributes power to multiple branch output ci… |
| Power Factor Controller symbol | The Power Factor Controller symbol represents an automatic power-factor-correction (APFC) relay that measures the reactive power in an AC system and switches capacitor bank stages… |
| Power Meter symbol | The Power Meter symbol represents an instrument that measures real power (kW), reactive power (kvar), apparent power (kVA), energy consumption (kWh), and power quality parameters… |
| Power Rail symbol | The Power Rail symbol represents a common distribution conductor in an industrial control-panel schematic, depicted as a vertical line with multiple tap points labelled Top, Mid,… |
| Power Supply 24V DC symbol | The Power Supply 24V DC symbol represents a switched-mode or linear AC-to-DC power supply that converts mains alternating current to a regulated 24 V DC output, depicted in indust… |
| Pressure Regulator symbol | The Pressure Regulator symbol represents a pneumatic or hydraulic device that reduces and maintains a downstream pressure at a set value regardless of upstream supply pressure flu… |
| Pressure Switch symbol | The Pressure Switch symbol represents an electromechanical or electronic device that opens or closes an electrical circuit when the sensed fluid pressure reaches a preset threshol… |
| PROFINET Connector symbol | The PROFINET Connector symbol represents an Industrial Ethernet network interface port used in PROFINET (Process Field Network) automation systems, depicted in schematic diagrams… |
| Proximity Sensor (Capacitive) symbol | The Proximity Sensor (Capacitive) symbol represents a non-contact electronic sensor that detects the presence of any material — metallic or non-metallic — within its sensing range… |
| Proximity Sensor (Inductive) symbol | The Proximity Sensor (Inductive) symbol represents a non-contact electronic sensor that detects the presence of ferrous and non-ferrous metal targets within its sensing range by m… |
| Pump (Motor-driven) symbol | The Pump symbol represents an electrically driven pump — typically a pool pump or centrifugal pump — in wiring diagrams, depicted as a motor body rectangle combined with a pump im… |
| Push Button NC symbol | The Push Button NC symbol represents a momentary normally-closed (NC) push button — standardised in IEC 60617-07 and ANSI Y32.2/IEEE 315 — whose contact is closed (conducting) in… |
| Push Button NO symbol | The Push Button NO symbol represents a momentary normally-open (NO) push button — standardised in IEC 60617-07 and ANSI Y32.2/IEEE 315 — whose contact is open (non-conducting) in… |
| RCA / Phono Connector symbol | The RCA / Phono Connector symbol represents a coaxial audio/video connector — standardised informally as the RCA plug — consisting of a central signal pin (Signal Centre) and a su… |
| RCD / RCCB symbol | The RCD / RCCB symbol represents a Residual Current Device (also called a Residual Current Circuit Breaker) — defined in IEC 61008 / IEC 61009 and specified in ANSI/UL 943 — a pro… |
| Relay Coil symbol | The Relay Coil symbol represents the electromagnetic coil of a relay — drawn as a rectangle (IEC 60617) or a circle/rectangle (ANSI Y32.2 / IEEE 315) — that, when energised by a c… |
| Relay NC Contact symbol | The Relay NC Contact symbol represents a Normally Closed (NC) relay or contactor contact — defined in IEC 60617-07 and ANSI Y32.2 / IEEE 315 — a two-terminal switching element (In… |
| Relay NO Contact symbol | The Relay NO Contact symbol represents a Normally Open (NO) relay or contactor contact — defined in IEC 60617-07 and ANSI Y32.2 / IEEE 315 — a two-terminal switching element (In,… |
| Relief Valve symbol | The Relief Valve symbol represents the normally closed pressure-control valve that limits maximum system pressure by diverting flow to tank when pressure exceeds its spring settin… |
| Reversing Valve symbol | The Reversing Valve symbol represents the pilot-operated four-way refrigerant valve that switches a heat pump between heating and cooling by swapping which coil receives the compr… |
| RJ45 / Ethernet Connector symbol | The RJ45 / Ethernet Connector symbol represents an 8P8C (8-position 8-contact) modular connector — standardised in IEC 60603-7 and TIA-568 — used to terminate Cat5e, Cat6, and Cat… |
| RTD Temperature Sensor symbol | The RTD Temperature Sensor symbol represents a Resistance Temperature Detector — a passive sensing element whose electrical resistance increases predictably with temperature — dep… |
| Safety Interlock Switch symbol | The Safety Interlock Switch symbol represents a mechanically actuated safety switching device that monitors the position of a physical guard, door, or cover and de-energises hazar… |
| Safety Light Curtain symbol | The Safety Light Curtain symbol represents an electro-sensitive protective device (ESPE) that creates an invisible infrared detection field across a machine access zone and genera… |
| Safety PLC symbol | The Safety PLC symbol represents a fail-safe programmable logic controller designed to execute safety-critical functions, depicted as a rectangular block with safety input pins (S… |
| Safety Relay Module symbol | The Safety Relay Module symbol represents a dedicated, certified relay module that monitors dual-channel safety inputs (e-stops, interlock switches) and provides forced-guided out… |
| Selector Switch 2-Position symbol | The Selector Switch 2-Position symbol represents a maintained-contact rotary or cam-operated switch that can be turned to one of two discrete positions, used in schematic and wiri… |
| Selector Switch 3-Position symbol | The Selector Switch 3-Position symbol represents a maintained-contact rotary switch with three discrete cam positions used in schematic and wiring diagrams per IEC 60617 and ANSI… |
| Single-Phase Motor symbol | The Single-Phase Motor symbol represents an AC electric motor powered by a single-phase supply, depicted in IEC 60617 as a circle containing the letter M (motor designator) with t… |
| Soft Starter symbol | The Soft Starter symbol represents a reduced-voltage motor-starting device drawn as a labeled rectangle with three input terminals (L1, L2, L3) and three output terminals (T1, T2,… |
| Soft Starter (3-Phase) symbol | The Soft Starter (3-Phase) symbol represents a reduced-voltage motor starting device that uses anti-parallel thyristor (SCR) pairs in each of the three supply phases — with line t… |
| Solenoid Valve symbol | The Solenoid Valve symbol represents an electrically operated fluid control valve drawn as a rectangle with a triangular flow indicator, two fluid-path terminals (In and Out) and… |
| Spark Plug symbol | The Spark Plug symbol represents an automotive or internal combustion engine ignition device drawn with a rectangular terminal body, a center electrode stem, and two horizontal ga… |
| Split-Core CT symbol | The Split-Core CT symbol represents a split-core current transformer — drawn as a circle or toroid with a gap indicating the openable core, secondary winding terminals (S1 and S2)… |
| Stack Light symbol | The Stack Light symbol represents a multi-segment machine status indicator (signal tower) whose stacked coloured lenses signal machine state at a distance, drawn as a vertical col… |
| Star-Delta Starter symbol | The Star-Delta Starter symbol represents a reduced-voltage motor-starting device drawn as a labeled rectangle with a Y-Δ (wye-delta) designation and six terminals — three supply i… |
| Starter Motor symbol | The Starter Motor symbol represents a high-current series-wound DC motor with an integral engagement solenoid that cranks an internal-combustion engine, shown in automotive wiring… |
| Stepper Motor (4-wire bipolar) symbol | The Stepper Motor (4-wire bipolar) symbol represents a precision electromechanical actuator drawn as a circle labeled 'M / STEP' with four coil terminals — A+ and A− for coil A, a… |
| Surge Arrester (SPD) symbol | The Surge Arrester (SPD) symbol represents a Surge Protective Device — a component connected between a line conductor and ground that limits transient overvoltages from lightning… |
| Surge Protector symbol | The Surge Protector symbol represents a surge protective device (SPD) connected between a supply conductor and earth — two terminals: Line and Ground — that remains high-impedance… |
| Switch (4-Way) symbol | The Switch (4-Way) symbol represents a double-pole double-throw (DPDT) intermediate switch used in North American residential wiring between two 3-way switches to enable control o… |
| Switch (DPST — 4-pin Rocker) symbol | The Switch (DPST — 4-pin Rocker) symbol represents a Double-Pole Single-Throw switch that simultaneously opens or closes two independent circuit poles with a single actuator, feat… |
| Temperature Switch symbol | The Temperature Switch symbol represents a thermally-actuated switching device that opens or closes an electrical circuit when a preset temperature threshold is reached, using a b… |
| Terminal Block symbol | The Terminal Block symbol represents a modular, insulated wire-termination device that provides a mechanically secure and electrically reliable connection point between wires or c… |
| Thermal Overload Relay symbol | The Thermal Overload Relay symbol represents a protective device—drawn as a set of heating elements (three rectangles or zigzag strips in series with the line conductors) paired w… |
| Thermocouple symbol | The Thermocouple symbol represents a temperature sensor consisting of two dissimilar metal wires joined at a measurement junction, drawn in circuit diagrams as two diagonal lines… |
| Time Delay Relay (Off-Delay) symbol | The Time Delay Relay (Off-Delay) symbol represents an electromechanical or electronic timing relay—drawn as a standard relay coil symbol with its associated contacts annotated wit… |
| Time Delay Relay (On-Delay) symbol | The Time Delay Relay (On-Delay) symbol represents an electromechanical or electronic timing relay—drawn as a standard relay coil (A1/A2 terminals) with associated contacts annotat… |
| Trailer Connector (4-pin Flat) symbol | The Trailer Connector (4-pin Flat) symbol represents a standardised four-circuit electrical connector used to interface a tow vehicle's lighting system with a trailer, drawn as fo… |
| Trailer Connector (7-pin) symbol | The Trailer Connector (7-pin) symbol represents a seven-circuit round electrical connector used to interface a tow vehicle with a heavy-duty trailer, drawn as a circular housing w… |
| TV Antenna (Yagi) symbol | The TV Antenna (Yagi) symbol represents a directional, parasitic-element antenna used for receiving or transmitting UHF/VHF television broadcast signals, recognised in IEC 60617-0… |
| Undervoltage Relay symbol | The Undervoltage Relay symbol represents a protective relay device that monitors supply voltage and trips its output contacts when the voltage falls below a preset threshold, stan… |
| UPS Block symbol | The UPS Block symbol represents an Uninterruptible Power Supply unit that conditions incoming AC power, maintains an internal battery, and provides uninterrupted AC output to crit… |
| Variable Transformer (Variac) symbol | The Variable Transformer (Variac) symbol represents an adjustable autotransformer in circuit diagrams, depicted as two magnetically coupled coils — or a single tapped coil — with… |
| VFD / Variable Frequency Drive symbol | The VFD / Variable Frequency Drive symbol represents a power-electronic drive unit used in electrical and industrial schematics to denote a device that converts fixed-frequency AC… |
| Voltage Transformer (PT) symbol | The Voltage Transformer (PT) symbol represents an instrument potential transformer used in electrical schematics to denote a precision two-winding transformer that steps down high… |
| Voltmeter symbol | The Voltmeter symbol represents a voltage-measuring instrument in circuit diagrams, depicted as a circle enclosing the letter 'V', connected in parallel across the two nodes whose… |
| Water Heater / Geyser symbol | The Water Heater / Geyser symbol represents an electric storage water heater in residential and commercial wiring diagrams, depicted as a cylindrical or rectangular tank block wit… |
| Water Level Probe (3 electrodes) symbol | The Water Level Probe (3 electrodes) symbol represents a three-electrode conductivity-based liquid level sensor used in circuit diagrams to indicate a device that detects High, Lo… |
| Wire Crossing (No Connection) symbol | The Wire Crossing (No Connection) symbol represents two conductors that cross each other in a schematic diagram without making an electrical connection, used per IEC 60617 and ANS… |
| Wire Duct / Trunking symbol | The Wire Duct / Trunking symbol represents an open-top or slotted plastic or metal channel used in wiring diagrams to denote a cable management system that organises, routes, and… |
| Wire Junction / Node symbol | The Wire Junction / Node symbol represents the point at which two or more conductors are electrically connected in a circuit diagram, depicted as a filled dot at the intersection… |
| Wire Label / Marker symbol | The Wire Label / Marker symbol represents a conductor identification tag, ferrule, or sleeve in wiring diagrams, drawn as a small flag, rectangle, or sleeve shape attached to a wi… |
| X-Ray Tube symbol | The X-Ray Tube symbol represents a vacuum tube that generates ionising X-radiation by accelerating electrons from a heated cathode filament toward a tungsten anode target, as used… |
| XLR Connector (3-pin Audio) symbol | The XLR Connector (3-pin Audio) symbol represents a balanced, shielded 3-pin audio interconnect in circuit diagrams, denoting a connector used to carry balanced differential audio… |
| XNX / 4-20mA Gas Transmitter symbol | The XNX / 4-20mA Gas Transmitter symbol represents a loop-powered industrial gas detection transmitter that outputs a 4–20 mA analogue current signal proportional to gas concentra… |
What are electrical wiring diagram symbols and their meanings?
Wiring diagram symbols are graphics that represent electrical functions or devices, such as switches, outlets, lights, fuses, breakers, motors, resistors, relay coils, transformers, and grounds. Many are standardized by IEC or ANSI/IEEE conventions; device-specific and pictorial symbols can vary by discipline, region, and manufacturer, so the drawing legend and authoritative standard still matter.
What do the most common wiring diagram symbols mean?
A line is a conductor; a junction dot means conductors connect. Parallel lines can denote a capacitor, a coil can denote an inductor or relay coil, and decreasing horizontal lines commonly denote earth ground. Switches show contact state. Always read these in the context of the drawing legend because pictorial and manufacturer conventions vary.
Are these electrical symbols free to use?
The DIY symbol pack and printable reference chart are free to use. Additional editor packs depend on the current plan shown in the product. Every published meaning and reference page remains publicly browsable.
Which circuit diagram symbols do I need for GCSE physics?
GCSE physics uses the IEC-style symbols for cell, battery, switch, lamp, resistor, variable resistor, thermistor, LDR, diode, LED, ammeter, voltmeter, and fuse. All of them are in the DIY and hobbyist packs above — click any symbol for its meaning and a worked example circuit.
What circuit symbols are taught in grade 6 to grade 8 science?
Middle-school circuits use a small set: cell/battery, wire, open and closed switch, bulb (lamp), resistor, and sometimes a buzzer or motor. Start with the DIY pack — each symbol page explains what the symbol means and how to draw it correctly.
What is the difference between IEC and ANSI circuit symbols?
IEC 60617 is the international symbol database, while legacy ANSI/IEEE conventions remain common in North American drawings. A familiar difference is the resistor: a rectangle in IEC diagrams versus a zigzag in many ANSI-style diagrams. Pages identify standard-specific forms only where that content has been verified.
Can I download these electrical symbols as a PDF chart?
Yes — download the free electrical symbols chart PDF directly (all symbols with names, grouped by category), or open the printable chart and print it from your browser. Every symbol on the chart links back to its full reference page.