What is relay for electrical ?

Question

What is relay for electrical ?

Answer 1

Its essentially a switch that controls one circuit, when power is supplied or dropped from another circuit.

It prevents high voltages/currents from having to run through the control circuit.

Answer 2

When the coil is energized, it breaks one contact, and makes another.  So it is basically an electrically controlled switch.

Answer 3

A relay is an electromagnetic switch.

The switch is normally in one position.

When you apply electricity to the coil or electromagnet, the switch flips to the other position.