What is relay? It is switch that provides the safety to an electrical circuits from the abnormal conditions. Relay has two parts which is NO ( normally open ) and NC ( normally close ). NO means the circuit are normally open, In this conditions the electric supply does not passes through the circuit due to the open circuit conditions. This type of relays are use in mechanical devices like hoist and manipulator for controlling. NC means the circuit is normally close, In this conditions the electric current can flow through the circuit due to the circuit is close And this relay coil is use as On switches in mechanical devices like hoist and manipulators.
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