Common Base

The Common Base circuit.

This circuit has low input impedance and high output impedance. Sometimes this is desirable, but rarely does it crop up for basic audio signal processing. Knowledge of how this circuit functions is important for tracing many practical circuits, especially power amps, where it's special features will couple with other circuit types to provide overall high performance.

Like the common emitter, this circuit can give voltage gain. Unlike the common emitter, the input and output are in-phase.