Electric Bell : How it works:
1. The button at the top (K) is closed.
2. Current flows through the solenoid (E). This produces a magnetic field.
3. This pulls the magnet (A) toward the solenoid. This bar hits the bell, creating a dinging noise.
4. When A goes up, it pulls away from T and hits B, the bell. This movement disconnects A from T and disconnects the circuit (the current no longer can flow in a full circle.)
5. Since the circuit is disconnected, the current flowing through the solenoid is stopped, and the magnetic field retracts.
6. Since the magnetic field is no longer there, A is no longer attracted to the solenoid, so A falls back down.
7. When A falls, it reconnects to T, and the circuit is complete again. The process restarts with steps 2-7 until K is no longer pressed.