What is the importance of IQ in a common emitter stage?

[Fusion916]

What need to be considered as far as choosing the IQ point of a common emitter stage intended to drive a common collector stage? I'm referring to the CE stage with an RC and RE.

I suppose meaning, what parameters do IQ effect?

Input resistance? Current drive capability? Open loop hfe? etc

 

[jerluwoo]

The short answer is that it affects all of the above. Below is a screen from a datasheet from a 2n3906 showing how parameters are affected by the difference in Iq.

 

[DUG]

Bandwidth, noise...the list goes on.

Design is a compromise where you pick some of what you want and the rest you get what you get.

lots of fun.