what is a relay?

A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts. Relays are found hidden in all sorts of devices. In fact, some of the first computers ever built used relays to implement Boolean gates.

It is a switch, nothing more, with either normally open contacts ( which means the contacts are not touching until the voltage is applied to the relay coil which closes the contacts to allow for a path completion ) or normally closed contacts ( which when voltage is applied to the coil part of the relay, it opens the contacts breaking the path. They come in all kinds of sizes from very small the size of pencil erasers to very large. This is due to the amps or load required for the circuit.

The relay is a switch that is used to control an electrical circuit. It could be normally open or normally close. it is operated by a coil which when energized it produces an electromagnetic force that pulls or push the contacts of the switch.

Yes, it is a switch, as other answerers have mentioned. However, newer solid-state power relays differ from magnetic-solenoid relays, and operate from low voltage (2 to 5 volts) direct current (dc)

It is a form of a switch. The switch is a an electrical magnet that pulls a lever down when a current is supplied connecting the circuit. It makes a clicking noise usually.

A electrical switch operated by a solenoid

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