Explian the working of a common-source amplifier and a common drain amplifier?

Answer 1

Configuration

Voltage Gain

Current Gain

Input Resistance

Output Resistance

Common- Source

AV >1

-

∞

Moderate to high

Source-Follower

AV ≈ 1

-

∞

Low

Common- Gate

AV > 1

Ai ≈ 1

Low

Moderate to high

Both the common-gate and common source has voltage gain of greater that 1 compared with the voltage gain of source- follower which is less than or approximately equal to 1 . The input resistance of both common-source and source follower is high typically ranges from kilo ohms and above while common-gate has a low input impedance ranges from hundred ohms or below. The output resistance of both common-gate and common-source are dominated by RD while source follower has low output impedance and is not dominated by RD

Answer 2

the common source amp, increase the input signal in terms of amplitude