BJT Construction

BJT CONSTRUCTION

The Bipolar Transistor basic construction consists of two PN-junctions producing three connecting terminals with each terminal being given a name to identify it from the other two. These three terminals are known and labeled as the Emitter (E), the Base (B) and the Collector (C) respectively.

Transistor Terminals

The transistor has three terminals term as emitter, collector, and base. The terminals of the diode are as following:

Emitter – The part of a transistor which supplies the large section of majority charge carrier is called emitter. The emitter is always connected in forward biased with respect to the base so that it enables supply of the majority charge carrier to the base. The emitter-base junction injects a huge amount of majority charge carrier into the base because it is heavily doped and moderate in size.

Collector – The part of a transistor which collects the major portion of the majority charge carrier supplied by the emitter is called a collector. The collector-base junction is always connected in reverse bias. Its main work or function is to remove the majority charges from its junction with the base. This portion of the transistor is moderately doped, but larger in size as compare to base and emitter so that it can collect most of the charge carrier supplied by the emitter.

Base – The section of the transistor is in between emitter and collector known as the base. The base section forms two circuits, the input circuit which is associated with the emitter and the output circuit associated with the collector. The emitter-base circuit connected in forward biased and offered the low resistance to the circuit. The collector-base junction is connected in reverse bias and offers the higher resistance to the circuit. The base of the transistor is very lightly doped and very thin because of which it offers the majority charge carrier to the base. As shown in the diagram below construction, symbol, and two diode analogy