How does a solenoid work?

A solenoid works by producing a magnetic field when electric current flows through its coiled wire. The magnetic field inside the solenoid is strong and nearly uniform.

When a soft iron core is placed inside the coil, the solenoid acts as an electromagnet. The strength of the magnetic field increases with more turns of wire or higher current.

Quick Fact: Solenoids are used in electric bells, relays, valves, and electromagnetic locks.