Bipolar Junction Transistor – Definition, Working, Symbol, Types, Uses & Characteristics

Define Bipolar Junction Transistor?

What is Bipolar Junction Transistor?

A bipolar junction transistor or BJT is a three terminal electronic gadget that amplifies the progression of current. It is a current controlled gadget. In bipolar junction transistor, electric flow is led by both free electrons and holes.
Not at all like a typical pn junction diode, the transistor has two p-n intersections.

Types or Sorts of Bipolar Junction Transistors (BJTs)

The bipolar junction transistor are framed by sandwiching either n-type or p-type semiconductor layer between sets of opposite polarity semiconductor layers.

Bipolar junction transistor are arranged into two types in light of their development: They are

1 NPN Transistor
2 PNP Transistor
NPN Transistor
Whenever a single p-type semiconductor layer is sandwiched between two n-type semiconductor layers, the transistor is supposed to be a NPN transistor.

PNP Transistor
At the point when a solitary or single n-type semiconductor layer is sandwiched between two p-type semiconductor layers, the transistor is supposed to be a pnp semiconductor.

Note– Both PNP and NPN semiconductors comprise of three terminals: they are emitter, base, and collector.

Terminals of Bipolar junction transistor
As the name proposes, the emitter area supplies the charge carriers. The emitter segment is intensely doped so it can infuse countless charge carriers into the base. The size of the emitter is always more than the base.
The center layer is called base. The foundation of the transistor is extremely flimsy or thin when contrasted with emitter and collector. It is delicately doped.
The function of the collector is to gather charge carriers. It is respectably doped. That is the doping level of the collector area is in the middle of Emitter and Base. The size of the collector is more noteworthy 100% of the time than emitter and base. The collector region in the transistor is extensively bigger than the emitter region. This is on the grounds that the collector locale needs to deal with more power than the emitter does and more surface region is expected for heat dissipation.

In transistor, the amplification is accomplished by passing input current from a region of low resistance to an area of high resistance.

Applications of Bipolar Junction Transistor – BJT
The different Applications of junction transistors include:
1. TVs
2. Cell phones
3. PCs
4. Radio transmitters
5. Sound speakers

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