Electromagnetism is used in many ways in electrical and electronic equipment.
In relays, an electromagnet attracts a metal piece which moves contacts from one circuit to another.
In a magnetic circuit breaker, a similar action to relays occurs, when excessive current flows through an electromagnet releases a latch which allows the contacts to open and move the handle to the "Off" or "Tripped" position. Many circuit breakers also use a bi-metal strip which heats up when current flows, and if the current is too high, the bi-metal strip bends to release the latch and trip the breaker. This is used to trip the breaker when a small overload occurs for a longer period of time, the magnetic trip operates very rapidly with a heavy overload.
In a loud speaker, a coil of wire fastened to the cone is alternatively attracted and repelled by a strong permanent magnet, moving the cone to reproduce sound.
In relays, an electromagnet attracts a metal piece which moves contacts from one circuit to another.
In a magnetic circuit breaker, a similar action to relays occurs, when excessive current flows through an electromagnet releases a latch which allows the contacts to open and move the handle to the "Off" or "Tripped" position. Many circuit breakers also use a bi-metal strip which heats up when current flows, and if the current is too high, the bi-metal strip bends to release the latch and trip the breaker. This is used to trip the breaker when a small overload occurs for a longer period of time, the magnetic trip operates very rapidly with a heavy overload.
In a loud speaker, a coil of wire fastened to the cone is alternatively attracted and repelled by a strong permanent magnet, moving the cone to reproduce sound.