Types of BJT Amplifiers
BJT works in the 3 configuration as mention below :
- Common Emitter (CE) Configuration
- Common Base (CB) Configuration
- Common Collector (CC) Configuration
Common Emitter (CE) Configuration
- The emitter terminal in this setup is shared by the input and output.
- It provides voltage gain and high power gain.
- Commonly used for amplifying weak signals.
In the CE configuration
According to the summing current law,
IE = IB + IC
IE -> Emitter current
IB -> Base Current
IC -> Collector current
Common Base (CB) Configuration
- The base terminal in this setup is shared by the input and output.
- It provides current gain and low input impedance.
- It is often used in high-frequency applications.
In the CB configuration
IE = IB + IC
Common Collector (CC) Configuration
- In common collector configuration, the collector terminal is common to both the input and output.
- It provides voltage gain less than unity but has high current gain.
- It is useful for impedance matching between stages of a multi-stage amplifier.
In CC configuration
IE = IB + IC
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