FAQ - How to choose between NPN and PNP sensor

Modified on Thu, 25 Sep at 12:50 PM

Q: Should I choose an NPN or a PNP sensor for my system?


A: The key to choosing correctly is checking what type of input the controller or system expects. If it needs a positive signal, use PNP; if it needs a negative signal, use NPN. 


PNP sensor: Provides a positive signal when activated (when the sensor detects an object).

This is often preferred when the controller or device is designed to recognize a positive voltage as “ON.”


NPN sensor: Provides a negative signal when activated. This type of sensor is preferred when the system is not designed to receive voltage. 



Date/Revision History

First review 09/25/2025 V1.0

Second review 09/25/2025 V1.1


Author: 

Hector Vega, Technical Support Engineer


References

Omron's sensors

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