Introduction to Relay

It is an electrical control device, which is an electrical appliance that causes the controlled quantity to undergo a predetermined step change in the electrical output circuit when the change in the input quantity (excitation quantity) meets the specified requirements. It has an interactive relationship between the control system (also called the input loop) and the controlled system (also called the output loop). Usually used in automated control circuits, it is actually an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.