Difference Between a NPN and a PNP Transistor

Difference between a npn and pnp transistor


The difference between a NPN transistor and a PNP transistor is their polarity and their actions are reversed:

Polarity Is Reversed


NPN Transistor Polarity

NPN Transistor

A NPN transistor conducts from emitter to collector.















PNP Transistor Polarity

PNP Transistor

A PNP transistor conducts from collector to emitter.












Actions are Reversed


NPN Transistor

This is how a NPN transistor works:

As you increase voltage to the base of a NPN transistor, the transistor is turned on more and more until it conducts fully from emitter to collector.

And as you decrease voltage to the base of a NPN transistor, the transistor turns on less and less, until the voltage is so low, the transistor no longer conducts across emitter to collector, and shuts off.

PNP Transistor

A PNP transistor functions the total opposite way.

As you increase voltage to the base of a PNP transistor, the transistor is turned off more and more until it no longer conducts and completely shuts off.

And as you decrease voltage to the base of a PNP transistor, the transistor turns on more and more, until the transistor fully conducts from collector to emitter.

HTML Comment Box is loading comments...