Electromagnetic Door Lock Simulation

The switch is open, so no current flows. The spring holds the pin in the door frame.

What is happening?

Starting position

Door locked

The circuit is open. The coil is not magnetic, and the spring pushes the locking pin into the door frame.

Current

Magnet strength

Spring compression

Try turning the power on.

Power source and switch: complete or break the circuit.

Coil: current flowing through the wire creates a magnetic field.

Iron core and armature: the core strengthens the field and attracts the moving metal armature.

Return spring: is compressed when the pin retracts and pushes it back when power is removed.

Locking pin: moves out of the door frame so the door can open.

Turn on the switch to complete the circuit.
Current flows through the coil around the iron core.
The core becomes an electromagnet and attracts the metal armature.
The armature pulls the locking pin out of the door frame and compresses the spring.
The unlocked door can now open.
Close the door and turn off the switch. The magnetic field disappears and the spring returns the pin to the locked position.