BJT Amplifiers

BJT (Bipolar Junction Transistor) amplifiers are designed to amplify signals in electronic devices. There are three types of BJT amplifiers: Common Emitter (CE), Common Base (CB), and Common Collector (CC).

Input Impedance and Voltage Gain

Input impedance refers to the measure of how much an amplifier resists the flow of signals into the input terminals, while voltage gain refers to the measure of how much an amplifier increases the voltage of an input signal.

CE, CB, and CC amplifiers all have different input impedance and voltage gain values. However, the CC amplifier offers the highest input impedance and the least voltage gain among the three types.

Cascode Amplifier

A cascode amplifier is a two-stage amplifier that combines the CE and CC amplifiers to improve their performance. It offers high input impedance and high voltage gain, making it an excellent choice for RF (Radio Frequency) applications.

However, the cascode amplifier requires extra components and is more complicated to design and implement than the CE, CB, and CC amplifiers.

Conclusion

In summary, the CC amplifier offers the highest input impedance and the least voltage gain among the three types of BJT amplifiers. The cascode amplifier, on the other hand, offers high input impedance and high voltage gain but requires more components and is more complicated to design and implement.