30 January 2018

What is NPN and PNP transistor

What is an NPN transistor?

NPN transistors are three-terminal, a three-layer device that can function as either amplifiers or electronic switches. 


In NPN transistor one p-type material is placed between two n-types materials is known as Negative-Positive-Negative type transistor. 


It amplifies the weak signals to enter into the base and produces strong amplify signals at the collector end. In NPN transistor, the direction of movement of an electron is from the emitter to collector region due to which current constitutes in the transistor. 


What is a PNP transistor? 

PNP transistors also are three-terminal, a three-layer device that opposite to NPN transistor where a positive DC voltage is applied to the emitter.  

In PNP transistor one n-type material is placed between two p-type materials is known as Positive-Negative-Positive type transistor.  

PNP transistor uses a small base current and a negative base voltage to control a much larger emitter-collector current. PNP transistor, the emitter is more positive with respect to the base and also a collector. 

The main difference between these two types of transistors is that the holes are more important carriers for PNP transistors, while electrons are more important carriers for NPN transistors. 
Both NPN and PNP transistor are the same in some way and related to each other but they may have differed from each other too. 

You can also check it out the difference between NPN and PNP transistor