DC Analysis of BJT Amplifier Circuits
For the DC analysis of the BJT, we are going to use common-emitter amplifier circuit as shown in below figure.
Thevenin’s theorem and Kirchoff’s voltage law are used to create a dc equivalent circuit after eliminating the coupling and bypass capacitors, the load resistor, and the signal source in the DC analysis of a common-emitter amplifier circuit.
We know capacitor block the D.C current so for the D.C analysis all the capacitor in the circuit will be open.
Frequency of D.C current is = 0
So XC = infinite , Open circuit ( that’s why block the dc current)
Then convert the this circuit into the Thevenin equivalent circuit.
Apply Input KVL get the value IBQ , ICQ .
Apply output KVL and get the value of the VECQ .
After getting all value plot the graph between IC and VCE as shown below
The intersection point is the Q-point,
B = VCC
A = VCC / RC
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