NO / NC – Optional
What’s is NC and NO in a door sensor?
NO (normally open), switch is closed when magnet come to the switch. Switch will open when magnet leave.
NC (normally closed), switch is open when magnet come to the switch. Switch will close when magnet leave.
NC- normally close NO- Normally open C- Common
NO or NC connections are given according to the requirement of end user.
If the system which we are connecting the relay module function normally on closed circuit connection and stops when the circuit is open we use NC connection. If there is any trigger to relay module the connection become closed and the system shut down.