[Exact] Comparison between CB, CC, CE Configuration of BJT



Bipolar Junction Transistor(BJT) has a total of three terminals that are Emitter, Base, and Collector. So when a BJT is to be connected in a circuit, it's one terminal that must be taken as the common terminal for both input and output. So, according to taking common terminal, there are three types of configurations that are Common Emitter or CE configuration, Common Base or CB configuration, and Common Collector or CC configuration.

These three transistor configurations have their own characteristics, advantages, and applications. So, let's go to know the comparison between CB, CC, and CE configuration and their characteristics, and applications.


Comparison between CB, CE, and CC Configuration


Characteristics
CB
CE
CC
Common Terminal for Input and Output
Base Terminal
Emitter Terminal
Collector Terminal
Input voltage applied between
Emitter and Base terminal
Base and Emitter Terminal
Base and Collector Terminal
Output Voltage taken across
Collector and Base Terminal
Collector and Emitter Terminal
Emitter and Collector Terminal
Input Impedance
Very Low(only 50 to 500 ohm)
Medium(500 to 5000 ohm)
Very high(200 to 750 kilo ohm)
Output Impedance
Very High(1 to 10 Mega Ohm)
Medium(50 to 500 kilo ohm)
Very Low( up to 50 ohm)
Input Current
Emitter Current or IE
Base Current or IB
Base Current or IB
Output Current
Collector Current or IC
Collector Current or IC
Emitter Current or IE
Output Signal Phase
Same phase with input
180 degree out of phase
Same phase with input
Current Gain
Always less than Unity
α = IC/IE
Between 35 to 500
β = IC/IB
Very High
γ = IE/IB
Voltage Gain
About 150
About 500
Less Than Unity
Leakage Current
Very Small
Very Large
Very Large
Power Gain
Medium
High
Medium
Application
High Frequency Circuits
RF Signal Processing
Switching Circuits



CB configuration of Transistor


In this configuration, the base terminal of the transistor is taken as the common terminal. Also, the Base terminal is connected to the ground. In this configuration, the input voltage is applied between the emitter and base terminal. And the output voltage is taken across the collector and base terminal. Here you can see the diagram below.

Transistor Common Base(CB) Configuration

Characteristics of CB Configuration


1. This configuration provides very low input impedance(only 50 to 500 ohm).

2. It provides very high output impedance(1 to 10 Mega Ohm).

3. In this configuration, the current gain is denoted by alpha(α) which is always less than unity(0.95 to 0.99).

4. In this configuration the output signal is always in the same phase as the input signal.


Application of CB configuration


1. Transistor CB configuration used in current-to-voltage converter circuits.

2. This configuration is used in very high-frequency applications.

3. This configuration is used to increase the impedance of the current source.


CE configuration of Transistor


In this configuration, the emitter terminal of the transistor is taken as the common terminal. And the emitter terminal is connected to the ground also. The input voltage is applied between the Base and Emitter terminal and the output voltage is taken across the collector and emitter terminal. Here you can see the diagram below.

Transistor Common Emitter(CE) Configuration

Characteristics of CE configuration


1. This configuration provides medium input impedance(500 ohm to 5000 ohm).

2. It provides very high output impedance(50 to 500 kilo Ohm)

3. In this configuration, the current gain is denoted by beta(β) which varies between 35 to 500

4. In this configuration, the phase difference between the output and input signal is 180 degrees out of phase.



Application of CE configuration


1. CE configuration is used RF signal processing circuits.

2. This configuration is used for audio amplifier circuits.

3. This configuration is used in sensor controller circuits.


CC configuration of Transistor


This is the most usable and simple configuration of transistors. In this configuration, the collector terminal of the transistor is used as a common terminal. And the Collector terminal is connected to the ground also. The input voltage is applied between the Base and Collector terminal and the output voltage is taken across the emitter and collector terminal. Here you can see the diagram below.

Transistor Common Collector(CC) Configuration

Characteristics of CC Configuration


1. This configuration provides very high input impedance(200 to 750 kilo Ohm).

2. It provides very low output impedance(up to 50 Ohm).

3. In this configuration, the current gain is denoted by gamma(γ) which is very high.

4. In this configuration, the output signal is always in the same phase as the input signal.


Application of CC Configuration


1. Transistor CC configuration is used for switching purposes.

2. This configuration is used for impedance matching.

3. This configuration is used in power amplifier circuits.

4. This configuration is used to make digital logic gates.



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[Exact] Comparison between CB, CC, CE Configuration of BJT [Exact] Comparison between CB, CC, CE Configuration of BJT Reviewed by Author on December 22, 2019 Rating: 5
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