BJT Amplifier Formula
In BJT we have CE, CC and CB :
Current Gain
We have Alpha (α) , Beta(β). Alpha (α) is defined as the ratio of the collector current to the base current α = IC / IB . Beta(β) is defined as the ratio of the collector current to the Emitter current β = IC/IE . We know that,
IE = IC + IB
Relation between α and β, given below
α = IC / IB => α . IB = IC ,
β = IC / IE => β . IE = IC ,
α = β / (β + 1)
IE = IC / α = IB.(1 + β)
IC -> Collector current
IB -> Base current
IE -> Emitter current
Current Loss
However a BJT has two P-N junctions and three terminals. When bjt is biased in its active region, the collector base jcn is reverse biased. The collector base junction reverse saturation current is the emitter current in the absence of base current. This is also called leakage current.
BJT Amplifier
Bipolar Junction Transistors (BJTs) have a long and diverse history of use in the electronics industry. They are used as a switching mechanism and for amplification in a wide range of applications. BJTs are highly sought after in power electronics because of their low turn on/off times, low voltage drop, high power, voltage, and current ratings, as well as their little leakage current when in blocking mode. In power electronics, they are mostly used for switching applications. The biasing conditions of the junctions dictate the three different modes of operation that bipolar junction transistors (BJTs) display: cut-off, active, and saturation.
A semiconductor device with three layers and three terminals that alternate between p-type and n-type layers is called a bipolar junction transistor (BJT). Three terminals in the BJT is the Collector, Base, Emitter. The arrangement of their layers distinguishes NPN and PNP, the two varieties of BJTs. The base of an NPN BJT is built of p-type material, whereas the emitter and collector are made of n-type material. On the other hand, the base of a PNP BJT is constructed of n-type material, while the emitter and collector are composed of p-type material. The collector-base junction (CBJ) and base-emitter junction (BEJ) are the two junctions found in a BJT.
Table of Content
- What is BJT Amplifier?
- Working Principle
- Types
- Characteristics
- BJT Amplifier Formula
- DC Analysis of BJT Amplifier Circuits
- Advantages and Disadvantages of BJT Amplifier
- Application of BJT amplifier