How To wire a 5-pin metal push button with an LED

To wire a 5-pin metal push button with an LED, start by analyzing the terminal layout: 5-pin configurations typically include a common (COM) pin, two normally open (NO) pins, and two normally closed (NC) pins, with NO/NC pairs electrically isolated when the button is idle.

First, connect the COM pin to a regulated power supply (3.3V or 5V, depending on LED specifications) using a 220Ω through-hole resistor—this component limits current to the LED, preventing thermal damage. Attach the LED’s anode (long lead) to one NO terminal; connect the cathode (short lead) directly to the system ground (GND) to establish the conduction path when the button is actuated.

For noise immunity, implement a 10kΩ pull-down resistor between the NO terminal and GND. This ensures the NO pin remains at logic low (0V) when the button is unpressed, eliminating floating voltages that could cause false triggers. If utilizing NC functionality for auxiliary switching, connect the second NC terminal to an alternate circuit path, though this is optional for basic LED operation.

Secure all connections with strain relief—crimp terminals or soldered joints are preferred for industrial environments—to withstand mechanical stress. Finally, validate the circuit: pressing the button should close the NO contact, allowing current to flow from COM → resistor → LED → GND, illuminating the LED. This configuration balances electrical safety, signal integrity, and operational reliability, suitable for human-machine interfaces in automation or consumer electronics.