Type of BJT Transistor

Bipolar junction transistor have three terminals which is emitter ,base and collector. By control the flow of current between base and emitter we can control the current flowing between emitter and collector.BJT have two type.Type of BJT transistor are given below.

type of BJT transistor

1-PNP Transistor

In this type of BJT transistor one n-type material is placed in between the two p-type materials.PNP transistor consist of 2 crystal diode which are connected in series. The transistor right side are known as collector-base diode and left side are known as emitter-base diode.

type of BJT PNP

2- NPN transistor

In this type of BJT one p-type material are placed in between the two n0type materials. This type of transistor are used to amplify the weak signals in electronic circuit. In his type of transistor electron move from emitter to collector as a result current flow from emitter to collector

type of BJT NPN

Terminal of transistor

Transistor has three terminals emitter ,base and collector All three terminal are discuss below

terminal of BJT
Type of BJT transistor


Emitter are the parts of transistor  which supply the majority carrier. The emitter of transistor is always connected in forward biased  with respect to base because the emitter supply the majority carrier to the base. As the base is lightly doped and the emitter –base junction inject heavy amount of majority charge carrier in to the base.


The collector of transistor are part of transistor which collects the majority charge carrier supplied by the emitter through base .The collector –base junction is always reverse bias because we need to remove the majority charge carrier from is junction with the base. The collector is moderately doped and size is too much large so it can collect the most of the majority charge carrier which supply from the emitter.


The base of transistor is the middle part which is heavy doped..The base connected with two circuit i-e input circuit with emitter and output circuit with collector. The emitter –base circuit is always forward bias offering very low resistance o the circuit and the collector-base junction is always reverse bias offering high resistance to the circuit. The base is very thin and lightly doped.

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