Sat Dec 18 02:47:12 EST 2010

PWM resistor

Found an idea on http://diystompboxes.com about using a pwm modulated
analog switch to create a variable resistor using 2 series resistors,
one bypassed.

Considering the simplest case, there are 2 possibilities: series and
parallel.  The point is, how is the switching averaged out?  I.e. PWM
really needs a lowpass filter.

In the series case, the filter would be an inductor, while in the
parallel case it would be a capacitor.

Hmm... doesn't it depend on what we want the resistor to do?  I.e. is
it a I->V or a V->I converter, meaning is it driven by a current or
voltage source respectively.