A relay is an electrically operated switch that opens and closes circuits by receiving electrical signals from outside sources. It receives an electrical signal and sends the signal to other equipment by turning the switch on and off. Relays are used to control a high power or high voltage circuit with a low power circuit, especially when galvanic isolation is desirable. They are used in a wide range of applications such as home automation, cars and bikes (automobiles), industrial applications, DIY Projects, test and measurement equipment, and many more. There are two main types of relays: mechanical relays and solid-state relays. Mechanical relays have contacts that are mechanically actuated to open/close by a magnetic force to switch signals, currents, and voltages ON or OFF. Solid-state relays, on the other hand, have no moving contacts but instead employ semiconductor and electrical switching elements such as triac and MOS FET to switch signals, currents, and voltages ON or OFF electronically.