Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal.
Accordingly, what do relays do?
Relays are switches that open and close circuits electromechanically or electronically. Relays control one electrical circuit by opening and closing contacts in another circuit. As relay diagrams show, when a relay contact is normally open (NO), there is an open contact when the relay is not energized.
Why is a relay used?
When the current is switched off, the contacts open again, switching the circuit off. A useful property of relays is that the circuit powering the coil is completely separate from the circuit switched on by the relay. For this reason relays are used where a safe low-voltage circuit controls a high-voltage circuit.
What is Relay and its application?
A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems.