Relay is an electrical switch component that is used to control load which requires more power and also the devices which can not be directly run by the power provided by digital or analog circuit boards.
Basically, a relay is made to work as a switching component when a very small voltage is triggered into it. A relay consists of two parts. One for accepting voltage from a small circuit and the other part simply completes the continuity of another circuit into which the main load is connected.
There are two different types of relays based on their process of working.