NPN Transistor vs. PNP Transistor
Process of Switching
What is NPN Transistor?
NPN Transistor is the type of bipolar transistor consisting up of p-type semiconductor that is affixed in between two n-type semiconductors. As we know that electrons are the majority carrier in NPN transistors, so the process of switching takes place rapidly in it than in the PNP transistors. As transistors are three connection semiconductor devices. In NPN three of the terminals are attached to each of the doped semi conductors. The p-type semiconductor is the base in this case and it is in the middle of the package, whereas on the left hand it is emitter and on the right it is the collector. The p-type base is connected to the negative potential, whereas the collector is connected to the positive potential. In NPN transistors a small current entering the base is amplified to produce a large collector and emitter current.
What is PNP Transistor?
PNP is the type of bipolar transistor consisting up of n-type semiconductor attached in between two p-type semiconductors. PNP transistors utilize a small base current and a negative base voltage to control a much larger emitter-collector current. As holes are the more important carriers in PNP, it has slightly slower switching time as compare to the NPN. That is because holes travel slowly than the electrons in NPN. PNP is exactly the opposite of NPN, and this can be further elaborated as in this n-typed base is connected to the positive terminal. Under many conditions it actually becomes quite hard to differentiate between NPN and PNP transistors just by looking at them. So in that case they are connected to multimeter and are determined by examining their current conduction with respect to their polarities.