Relay is one of the most important electromechanical devices highly used in industrial application specifically in automation. A relay is used for electronic to electrical interfacing i.e. it is used to switch on or off electrical circuits operating at high AC voltage using a low DC control voltage.Relays are available in different operating voltages like 6V, 12V, 24V etc. A relay generally has two parts a coil which operates at the rated DC voltage and a mechanically movable switch. The electronic and electrical circuits are electrically isolated but magnetically connected to each other, hence any fault on either side does not affects the other side.