Re: Base Bias Constant Voltage Source


dgc wrote:
> I guess the bottom line is that the only thing that should be acting on the
> BE junction is the signal. If the signal current causes even small changes
> in the bias voltage the transistor output will not be a true representation
> of the
> amplified signal. Is that basically it?

you are probably looking at a Class AB or C amplifier design. When the
RF input is large the BE junction will rectify and pull current. If
you want to keep the xistor at a fixed bias settng the base voltage
should be held steady despite the change in base current that occurs
due to the changing RF drive...

This is less of a problem in class A amplifers that do not pull base
current because the input signal is small and does not cause
rectification in the BE junction.

Mark
..

.

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