- A relay is a device that opens or closes an auxiliary contact under some predetermined condition in the main circuit.
- It also provides complete electrical isolation between the control circuit and power circuits.
- Main parts of relay are armature contacts and coil.
- it has normally open (NO) contact which can be closed by action of relay. It has normally closed (NC) which can be opened by action of relay.
- Relay can be operated for 6v, 12v, 18v, 24v, 48v, 110v, DC or AC.
- When current flows through the coil, the armature is attracted and operates the contact.
- By one relay several sets of contact may be operated.
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