Semiconductor relays

What is a relay?

A relay is a simple electromechanical switch that connects or disconnects two circuits. It uses an electrical signal to control an electromagnet, which in turn turns another circuit on or off. Relays are used to protect the electrical system and to minimize damage to equipment connected in the system due to overcurrent/voltages. They are also used to control a high-voltage circuit with a low-voltage signal, and in high-current circuits with a low-current signal. They can detect and isolate faults occurring in the power transmission and distribution system. Relays are intended for either AC circuit or DC circuit. In the case of AC relays, for each current zero position, the relay coil is demagnetized and hence there will be a chance of continued open circuit.