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Can we use NPN instead of PNP?
Generally, the PNP transistor can replace NPN transistors in most electronic circuits, the only difference is the polarities of the voltages, and the directions of the current flow. PNP transistors can also be used as switching devices and an example of a PNP transistor switch is shown below.
How can I use PNP as a switch?
For a PNP transistor, the Emitter potential must be positive with respect to the Base. Then the transistor operates as a “single-pole single-throw” (SPST) solid state switch. With a zero signal applied to the Base of the transistor it turns “OFF” acting like an open switch and zero collector current flows.
What does it mean to switch PNP and NPN?
“Switched” refers to which side of the controlled load (relay, small indicator, PLC input) is being switched electrically. Either the load is connected to Negative and the P ositive is switched ( P NP), or the load is connected to Positive and the N egative is switched ( N PN). These diagrams illustrate the differences between the two connections.
Can a PNP sensor be connected to a NPN sensor?
(Fuse) It generally does not matter if you use NPN or PNP sensors provided they are all connected to the PLC using isolated commons. You cannot mix PNP and NPN sensors on the same common point for inputs to the PLC.
Can you mix PNP and NPN on a PLC?
You cannot mix PNP and NPN sensors on the same common point for inputs to the PLC. If you do mix the sensors, then the different common points on the PLC must be isolated from each other.
How are PNP and NPN junctions used in a circuit?
As both the PN Junctions are reverse biased, there is almost no current flow except small leakage currents (usually in the order of few nano amps or pico amps). BJT in this mode is switched OFF and is essentially an open circuit. Cutoff Region is primarily used in switching and digital logic circuits.