Difference Between NPN Transistor and PNP Transistor

Main Difference

A transistor is the semiconductor device having three connections; it is capable of amplification in addition to rectification. Unlike FET transistors, Bipolar Junction Transistors (BJT) are the current-controlled devices that are capable of current rectification. BJT can further be divided into two types of transistors that can easily be differentiated. NPN Transistor is the type of bipolar transistor consisting up of p-type semiconductor that is affixed in between two n-type semiconductors, whereas PNP is the type of bipolar transistor consisting up of n-type semiconductor attached in between two p-type semiconductors. The other most notable difference between two of them is that holes are the more important carriers in PNP transistors, while electors are the more important carriers in NPN transistor.

Comparison Chart

NPN TransistorPNP Transistor
StructureNPN Transistor is the type of bipolar transistor consisting up of p-type semiconductor that is affixed in between two n-type semiconductors.PNP is the type of bipolar transistor consisting up of n-type semiconductor attached in between two p-type semiconductors.
CarrierElectrons are the more important carriers in NPN transistor.Holes are the more important carriers in PNP transistor.
Process of SwitchingFastSlow
BaseThe p-type base is connected to the negative potential in NPN.In NPN n-type base is connected to the positive terminal.

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.

NPN Transistor vs. PNP Transistor

  • NPN Transistor is the type of bipolar transistor consisting up of p-type semiconductor that is affixed in between two n-type semiconductors, whereas PNP is the type of bipolar transistor consisting up of n-type semiconductor attached in between two p-type semiconductors.
  • Holes are the more important carriers in PNP transistors, while electrons are the more important carriers in NPN transistor.
  • Electrons are the majority carrier in NPN transistors, so the process of switching takes place rapidly in it than in the PNP transistors.
  • The p-type base is connected to the negative potential in NPN, whereas in NPN n-type base is connected to the positive terminal.

Comparison Video

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Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss

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