What's the difference between a bjt fixed bias with and without an emitter resistor?

Question

input impedance? output impedance? voltage gain? current gain? others?

Answer 1

Since the emitter resistor is normally bypassed with a capacitor, none of the parameters would change.

But without the emitter resistor the bias would tend to be unstable, changing from transistor to transistor, and with temperature.

edit, no bypass.

Input Z goes up (emitter resistor provides negative feedback)

output Z stays the same

Voltage gain goes down

current gain stays the same, that is a property of the transistor.

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