LED Strip Symbol

Definition: 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 lines — with two polarity-sensitive terminals (12V+ and GND) fed from a Class 2 LED driver, per IEC 60617 LED symbol conventions and UL 2108 / UL 8750 low-voltage lighting practice.

Also known as: LED tape light, LED ribbon light, strip light, 12V LED strip, 24V LED strip, SMD 5050 strip, COB LED strip, under-cabinet tape light.

What the LED Strip symbol means

The LED Strip symbol denotes a flexible printed-circuit ribbon populated with surface-mount LEDs and current-limiting resistors, powered by low-voltage DC — most commonly 12 V or 24 V. The strip is organized into repeating segments (typically three LEDs plus a resistor per segment on a 12 V strip, six LEDs on a 24 V strip); each segment is an independent series string, and all segments sit in parallel across the strip's + and − rails. This segment structure is why strips can be cut to length, but only at the marked cut lines between segments.

Because the LEDs are diodes, the strip is polarity sensitive: connecting 12V+ and GND backwards produces no light (and no damage on plain single-color strips, since the LEDs simply block). The symbol's dashed cut-line marks and diode arrows communicate the two facts an installer needs from a diagram: where the strip may be cut, and which conductor is positive.

How to identify the LED Strip symbol

In wiring diagrams the LED strip is drawn as a long, thin rectangle with several LED symbols inside — the IEC 60617 diode triangle-and-bar with two small arrows radiating from it — and dashed vertical lines marking the cut points. The two pins exit one end, labelled with the supply polarity (12V+ or 24V+, and GND/−). RGB and RGBW variants are drawn the same way but with 4 or 5 pins (V+, R, G, B, and W), because color strips switch each color channel's cathode line, not the common positive.

There is no dedicated ANSI symbol for an LED strip; both IEC- and ANSI-style diagrams improvise from the standard LED symbol, so the elongated outline, repeated diode marks, and cut lines are the identifying features. Do not confuse it with an addressable strip (WS2812/NeoPixel style), which adds a third Data pin and cannot be dimmed with a simple PWM voltage dimmer.

Function in a circuit

The strip converts constant DC voltage into light through parallel banks of resistor-ballasted LED strings. Feed 12 V (or 24 V) across the rails and every segment conducts its designed current — typically about 20 mA per string on classic SMD 5050 strips. Total current scales linearly with length: a strip rated 3 W per foot draws 0.25 A per foot at 12 V, so a 16.4 ft (5 m) reel is roughly 4 A. This is why the power source must be a constant-voltage LED driver sized with 20% headroom, and why long runs are fed from both ends or in a star topology.

Voltage drop along the strip's thin copper rails is the dominant design constraint: past roughly 16 ft at 12 V (or about 32 ft at 24 V for equivalent gauge), the far end visibly dims and shifts color. The fixes are higher voltage strips (24 V or 48 V), heavier feed wire, injection points every 15–30 ft, or COB strips with better rail copper. Dimming is done by PWM on the DC side (a low-voltage PWM dimmer or smart controller), or by a TRIAC-dimmable driver on the AC side driving the strip at full DC.

Standards: IEC vs ANSI

Terminals / pins

Typical values

Common supply voltages are 12 V DC and 24 V DC (5 V for addressable, 48 V for long commercial runs). Power density runs from about 1.5 W/ft (4.9 W/m) for accent-grade 2835 strips to 4.5+ W/ft (15 W/m) for high-output or COB strips; current at 12 V is power ÷ 12 (a 5 m, 60-LED/m 5050 strip draws roughly 3.3–4 A). Cut intervals are typically every 3 LEDs (50–100 mm) at 12 V and every 6 LEDs at 24 V. Practical single-feed run length is about 16 ft (5 m) at 12 V and 32 ft (10 m) at 24 V before voltage drop demands power injection. Color temperatures span 2200–6500 K; CRI 80/90/95 grades are standard.

Where the LED Strip symbol is used

• Under-cabinet task lighting in kitchens, fed from a driver in an adjacent cabinet or above the wall cabinets
• Cove, toe-kick, and tray-ceiling accent lighting in living spaces, usually on a PWM or smart dimmer
• Closet and pantry lighting, often switched by a door contact or PIR motion sensor
• TV/desk bias lighting and gaming setups (single color, RGB, or addressable variants)
• Vehicle, RV, and marine 12 V accent lighting running directly from the battery bus through a fuse
• Retail displays, shelving, and signage, where aluminum channel with a diffuser doubles as a heatsink

Example

In an under-cabinet lighting diagram, a 24 V 60 W Class 2 LED driver's DC+ output feeds the strip's 24V+ pin through a PWM dimmer, and the driver's DC− returns from the strip's GND pin. The run is 4 m of 9.6 W/m strip (38.4 W total, within the driver's 80% loading rule), cut at the marked line after the last cabinet, with the cut end capped. Because the load sits at 38 W on a 60 W driver and the run is under 5 m, no secondary power-injection feed is needed.

Key facts

• LED strips are polarity-sensitive DC loads: reversed + and − simply produces no light on single-color strips because the LEDs block.
• Strips can only be cut at the marked cut lines (every 3 LEDs on 12 V strips, every 6 on 24 V), because each segment is a complete series string with its own resistor.
• Current scales with length — about 0.25 A per foot at 12 V for a 3 W/ft strip — so size the constant-voltage driver with at least 20% headroom.
• Voltage drop limits a single 12 V feed to roughly 16 ft (5 m); go to 24 V, heavier feed wire, or inject power at multiple points for longer runs.
• Pin count identifies the type: 2 pins = single color, 4 = RGB (common anode V+), 5 = RGBW, 3 pins (V+, GND, Data) = addressable (WS2812/SK6812 class).
• US installs fall under NEC Article 411 and Class 2 limits (max 60 W per output at 12 V), which is why big projects use multi-output drivers.
• Dim single-color strips with a DC-side PWM dimmer or a TRIAC-dimmable driver — never a standard AC wall dimmer directly on a non-dimmable driver.
• COB (chip-on-board) strips give a continuous dot-free light line and generally tolerate longer runs than discrete SMD 5050/2835 strips.

Frequently asked questions

What does the LED strip symbol look like in a wiring diagram?

A long thin rectangle containing repeated LED symbols — the diode triangle-and-bar with two small radiating arrows from IEC 60617 — plus dashed vertical lines marking the cut points. Two labelled pins (12V+/24V+ and GND) exit one end. RGB versions show 4 pins and RGBW 5; a third 'Data' pin means it is an addressable strip, which is a different animal electrically.

Can I cut an LED strip anywhere?

No — only at the marked cut lines (usually a dashed line with scissor icon and solder pads). Each segment between cut lines is a complete series circuit of LEDs plus a resistor; cutting mid-segment kills that segment's LEDs. Cut intervals are typically every 3 LEDs (about 2–4 inches) on 12 V strips and every 6 LEDs on 24 V strips.

What is the difference between 12V and 24V LED strips?

24 V strips run half the current for the same wattage, so they suffer less voltage drop and support runs about twice as long (roughly 32 ft vs 16 ft from a single feed) with finer-looking results at the far end. 12 V strips have shorter cut intervals (every 3 LEDs vs 6) and suit vehicles and battery systems. Never connect a 12 V strip to a 24 V supply — it will burn out the LEDs.

Why does my LED strip get dimmer at the far end?

Voltage drop in the strip's thin copper power rails. Every foot of strip carries the current of all the segments beyond it, so the voltage sags along the run and the far LEDs receive less than rated voltage. Fixes: feed the strip from both ends, add power-injection feeds every 15–30 ft, use heavier feed wire, or switch to a 24 V or 48 V strip.

What power supply do I need for an LED strip?

A constant-voltage DC driver matching the strip voltage (12 V or 24 V), rated at least 20% above the strip's total wattage. Compute wattage as the strip's W-per-foot (or W-per-meter) times the run length — e.g. 13 ft of 3 W/ft strip = 39 W, so use a 50–60 W driver. For US installs, a UL-listed Class 2 driver keeps the wiring under NEC low-voltage rules.

What is the difference between an LED strip and an addressable (WS2812) strip?

A standard strip lights every LED identically from a constant-voltage supply and dims via PWM on the whole rail. An addressable strip has a driver IC per LED (or per group) and a third Data pin carrying a serial protocol from a microcontroller, letting every pixel show a different color. Addressable strips usually run at 5 V or 12 V and cannot be controlled by a simple analog/PWM dimmer.

Related symbols

• DC Barrel Jack symbol
• LED symbol
• Low Voltage Transformer symbol
• RGB LED (4-pin) symbol
• Under-Cabinet Light symbol
• WS2812 Addressable LED symbol

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