What is a relay?
A relay is an electromechanical switch that performs the closing and opening of circuits electronically as well as electromechanically. It controls the opening and closing of the circuit contacts of an electronic circuit. When the relay contact is open (NO), the relay is not energized with the open contact. However, if it is closed (NC), the relay is not energized given the closed contact. However, when electrical energy is supplied, the states are prone to change.