A 4-pin switch is a device with four terminals used to control electrical circuits. Common types:
- DPST (Double Pole Single Throw): Two separate circuits switched on/off together. Pins: two inputs and two outputs.
- DPDT (Double Pole Double Throw): Two circuits switched between two outputs. Pins: two common (inputs) and four throws (outputs pairs).
- Illuminated switch: two pins for the switch contacts, two for the LED (with polarity).
Wiring tips:
- Identify pin layout from datasheet or markings (COM, NO, NC, LED +/−).
- For DPDT, use cross-wiring for reversing polarity (e.g., motor direction).
- Include proper voltage/current ratings and fuses.
Observe LED resistor needs and polarity.
Red LED Light on when the switch is on
Red LED Light Always on