SENSORS: NPN VS PNP

NPN VS PNP

In industrial sensors has been used for control applications. The sensors are divided into two types which are NPN and PNP. The NPN and PNP type of transistor that includes the most of the sensors.The principals are same as NPN and PNP transistor switching terms, also the differents are same but the working principals slightly differ. The difference is:-

PNP
The PNP sensors only switching the positive side of the circuits as the below picture. PNP 3- wire sensor circuit connection which is most of the industrial using it. The picture explaining that the sensor has 3-wire, the wire #1(positive supply wire) connected to the
(+ VDC), #2 wire connected to the LOAD, PLC input card, relays and the #3 wire connected to
(- COM). The working principal is when the sensor detected any objects the switch will turn to close the loop and the current flow into the PLC/LOAD as show the below picture.

NPN
The NPN sensors only switching the negative side of the circuits as the below picture. NPN 3- wire sensor circuit connection which is most of the industrial using it. The picture explaining that the sensor has 3-wire, the wire #1(negative supply wire) connected to the
(- COM), #2 wire connected to the LOAD, PLC input card, relays and the #3 wire connected to
(- VDC). The working principal is when the sensor detected any objects the switch will turn to close the loop and the current flow into the PLC/LOAD as show the below picture.