Types of transistors – BJT & FET

Types of Transistors - BJT & FET
Types of transistors

A Transistor is a semiconductor device which is used to amplify or switch electronic signals and electrical power. There are various types of transistors like BJT & FET.

So, let us know more about transistors.

Transistor is an acronym of two terms: “transfer-of-resistor.”

Thus, it is called Transistor.

In other words, the internal resistance of transistor transfers from one value to other values depending on the biasing voltage applied to the transistor.

Difference between BJT & FET

Bipolar junction transistor (BJT)
Field effect transistor (FET)
1. It is a bipolar device.1. It is uni-polar device.
2.In this type of transistor the operation is dependent on both of the charge carriers.2.In FET the operation performed is due to majority of carriers it may be either electrons or holes.
3.This device is current controlled.3. This device is voltage controlled.
4. Consumption of power is more.4. Consumption of power is less.
5. The offset voltage is required.5. The offset voltage is not required.

Bipolar junction transistor (BJT)

  • It includes PN diodes linked back-to-back, producing three connecting terminals called the Emitter (E), the Base (B) and the Collector (C).

  • For example, BJT can be used as an amplifier (analog electronics) and logic switches (digital electronics).

Types of BJT

1. In NPN transistor a thin layer of P-type semiconductor is sandwiched between two layers of N-type semiconductor.

2. Similarly, in PNP transistor a thin layer of N-type semiconductor is sandwiched between two layers of P type semiconductor.

Types of transistor, NPN and PNP transistor
NPN and PNP transistor
  • Since a PNP transistor works more or less the opposite of an NPN, it can be used where negative voltages are involved.
  • For example, amplifying an AC signal for driving a speaker.
  • Also, ICs are used everyday which are build up of transistors.
  • In short, the only difference between the NPN and PNP transistor is in the direction of the current.

Also read about >> Integrated Circuit

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