JST Connector (4-pin) Symbol

Q: What does the JST Connector (4-pin) symbol mean in a circuit diagram?

The JST Connector (4-pin) symbol represents a four-circuit miniature polarised connector used for removable multi-wire connections. Its four pins (P1–P4) carry combinations of power supply, ground, and data signals such as I2C, servo control, or balance charging leads, in a compact keyed housing that prevents reverse insertion.

Q: What does the JST 4-pin symbol look like on a schematic?

The JST 4-pin symbol appears as a small rectangular block labeled 'JST 4-pin' or 'JST 4P' with four equally-spaced pins — P1, P2, P3, P4 — emerging from one side. It is drawn similarly to a 4-position pin header, distinguished by the JST label and pitch annotation (e.g., 2.0 mm PH).

Q: What is a JST 4-pin connector used for?

JST 4-pin connectors are used for I2C sensor modules (VCC, GND, SDA, SCL), LiPo 3S battery balance leads, drone ESC telemetry wiring, servo extensions in robotics, and RS-485 device cables where four conductors must be routed and disconnected together in a compact, vibration-resistant plug.

Q: What is the difference between JST PH and JST XH 4-pin connectors?

JST PH (2.0 mm pitch, 4-pin) is rated 2 A per contact and has a total housing width of approximately 10.9 mm; it is common for small drone and sensor wiring. JST XH (2.5 mm pitch, 4-pin) is rated 3 A per contact and is wider at approximately 14.0 mm; it is used in applications requiring higher current such as LiPo balance leads for larger battery packs.

Q: Are JST 4-pin connectors polarised?

Yes. JST 4-pin connectors have an asymmetric housing key that physically prevents insertion in the wrong orientation, ensuring that P1 always connects to P1, P2 to P2, and so on. This polarisation protects against wiring errors that could damage sensitive electronics or reverse the polarity of a battery charger connection.

Q: What standard defines JST 4-pin connectors?

JST connectors are specified by JST Co. Ltd.'s own series datasheets (PH, XH, SH, etc.) for dimensions, current ratings, and contact specifications. IEC 60603 covers miniature connectors in principle, and IEC 60617 / ANSI Y32.2 / IEEE 315 govern schematic symbol conventions. The specific JST series dimensions are proprietary and defined in JST's manufacturer documentation.

Q: What is the designator for a JST 4-pin connector in a schematic?

JST connectors use the reference designator J (socket/jack, board-mounted) or P (plug, cable-mounted) per IEC 60617 and ANSI Y32.2 / IEEE 315, numbered sequentially, e.g., J2 for the second board socket or P2 for the mating cable plug.

The JST Connector (4-pin) schematic symbol. Standard-specific details are listed below where available.

Definition: 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 with pins P1, P2, P3, and P4, used for multi-conductor signal and power connections in robotics, sensor wiring, and embedded electronics per IEC 60617 general connector conventions and ANSI Y32.2 / IEEE 315.

Also known as: JST 4-pin, JST PH 4-pin, 4-pin JST plug, 4-circuit JST connector, JST 4-way connector.

What the JST Connector (4-pin) symbol means

The JST Connector (4-pin) symbol denotes a four-circuit miniature polarised plastic housing connector manufactured to JST dimensional series specifications. In schematic diagrams it marks a removable multi-conductor connection point for carrying combined power and signal lines — for example, VCC, GND, SDA, and SCL for an I2C sensor module, or four servo wires on a multi-axis robot.

The four pins P1–P4 are arranged in a single row within a keyed housing that prevents reverse insertion. JST 4-pin connectors are widely used in drone ESC-to-flight-controller wiring, servo extensions, battery balance leads, and peripheral sensor modules where a compact, secure, multi-wire plug is needed.

How to identify the JST Connector (4-pin) symbol

The JST Connector (4-pin) symbol is drawn as a rectangular block with four equally spaced pins emerging from one edge, labeled P1, P2, P3, and P4. The block is annotated 'JST 4-pin' or 'JST 4P' along with the pitch (e.g., 2.0 mm PH or 2.5 mm XH). It resembles a 4-pin header symbol but with the JST label indicating the specific crimped-contact connector type.

Function and usage boundary

The JST 4-pin connector provides four electrically isolated, mechanically retained contacts in a single compact housing, enabling simultaneous connection or disconnection of four conductors. Each contact is crimped onto the wire end, offering low contact resistance and resistance to vibration loosening. Common wiring assignments include VCC/GND plus two data lines for I2C peripherals, four motor phase signals for stepper motors, or combined power and differential signal pairs for RS-485 devices.

Standards: IEC vs ANSI

IEC 60617	IEC 60603 series covers miniature connectors in general. JST's own series specifications (PH, XH, SH, PA, etc.) define pitch and current ratings. IEC 60617 general connector block symbol conventions apply for schematic representation.
ANSI/IEEE 315	ANSI Y32.2-1975 / IEEE 315-1975 use a labeled multi-pin connector block for JST-type connectors; physical dimensions follow JST proprietary specifications.
Key difference	Both IEC and ANSI schematics represent the JST 4-pin as a labeled 4-pin connector block. The physical connector dimensions are defined by JST Co. Ltd. series specifications, not by IEC 60603 or ANSI directly.

The displayed SVG is the live editor implementation, not a licensed reproduction or certification of an IEC or IEEE database glyph. Verify the exact official entry and project edition before issuing work.

Logical terminals

Logical ID	Editor terminal name
p1	P1
p2	P2
p3	P3
p4	P4

Where the JST Connector (4-pin) symbol is used

Servo cable connections in multi-axis robots and RC aircraft (VCC, GND, and signal lines per servo)
I2C sensor module wiring (VCC, GND, SDA, SCL on a 4-pin connector)
LiPo battery balance leads for charging (2S balance connector uses 3 pins, 3S uses 4 pins)
Drone ESC telemetry and signal wiring between flight controller and electronic speed controllers
Panel display modules connecting data bus, power, and ground to an MCU
RS-232 or RS-485 device cables where four wires (TX, RX, GND, VCC or A, B, GND, VCC) are routed together

Key facts

The JST Connector (4-pin) symbol represents a 4-circuit miniature polarised connector with pins P1–P4, available in JST series including PH (2.0 mm pitch), XH (2.5 mm pitch), and SH (1.0 mm pitch).
The housing is polarised by an asymmetric key, physically preventing reverse insertion and protecting circuits from misconnection.
Current ratings per contact are 1 A for SH (1.0 mm), 2 A for PH (2.0 mm), and 3 A for XH (2.5 mm); total connector current capacity is limited to the single-contact rating when multiple contacts share a ground.
JST 4-pin connectors are commonly used for LiPo 3S balance leads, where P1 = cell 1 positive, P2 = cell 2 junction, P3 = cell 3 junction, and P4 = pack negative.
Crimped contacts provide vibration resistance and consistent contact resistance (<20 mΩ), making JST connectors preferred over friction-fit DuPont connectors in mobile and airborne applications.
IEC 60617 and ANSI Y32.2 / IEEE 315 represent the JST 4-pin as a general multi-pin connector block; physical dimensions are defined by JST proprietary series datasheets.
The standard reference designator for any connector, including JST 4-pin, is J (socket) or P (plug) per IEC 60617 and ANSI Y32.2 / IEEE 315.

Frequently asked questions

What does the JST Connector (4-pin) symbol mean in a circuit diagram?

The JST Connector (4-pin) symbol represents a four-circuit miniature polarised connector used for removable multi-wire connections. Its four pins (P1–P4) carry combinations of power supply, ground, and data signals such as I2C, servo control, or balance charging leads, in a compact keyed housing that prevents reverse insertion.

What does the JST 4-pin symbol look like on a schematic?

The JST 4-pin symbol appears as a small rectangular block labeled 'JST 4-pin' or 'JST 4P' with four equally-spaced pins — P1, P2, P3, P4 — emerging from one side. It is drawn similarly to a 4-position pin header, distinguished by the JST label and pitch annotation (e.g., 2.0 mm PH).

What is a JST 4-pin connector used for?

JST 4-pin connectors are used for I2C sensor modules (VCC, GND, SDA, SCL), LiPo 3S battery balance leads, drone ESC telemetry wiring, servo extensions in robotics, and RS-485 device cables where four conductors must be routed and disconnected together in a compact, vibration-resistant plug.

What is the difference between JST PH and JST XH 4-pin connectors?

JST PH (2.0 mm pitch, 4-pin) is rated 2 A per contact and has a total housing width of approximately 10.9 mm; it is common for small drone and sensor wiring. JST XH (2.5 mm pitch, 4-pin) is rated 3 A per contact and is wider at approximately 14.0 mm; it is used in applications requiring higher current such as LiPo balance leads for larger battery packs.

Are JST 4-pin connectors polarised?

Yes. JST 4-pin connectors have an asymmetric housing key that physically prevents insertion in the wrong orientation, ensuring that P1 always connects to P1, P2 to P2, and so on. This polarisation protects against wiring errors that could damage sensitive electronics or reverse the polarity of a battery charger connection.

What standard defines JST 4-pin connectors?

JST connectors are specified by JST Co. Ltd.'s own series datasheets (PH, XH, SH, etc.) for dimensions, current ratings, and contact specifications. IEC 60603 covers miniature connectors in principle, and IEC 60617 / ANSI Y32.2 / IEEE 315 govern schematic symbol conventions. The specific JST series dimensions are proprietary and defined in JST's manufacturer documentation.

What is the designator for a JST 4-pin connector in a schematic?

JST connectors use the reference designator J (socket/jack, board-mounted) or P (plug, cable-mounted) per IEC 60617 and ANSI Y32.2 / IEEE 315, numbered sequentially, e.g., J2 for the second board socket or P2 for the mating cable plug.

Related symbols

Physical breadboard, PCB, and panel mapping

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