[sdiy] emulating bi-polar capacitors

[David G Dixon]

> One thing I would be careful on is thinking two 47uFs back to back gives a
23uF capacitor.  It probably should at low applied voltages but as voltage
increases you may see an increase in capacitance as the reversed one tends
towards a short.  

This is where I believe that people tend to overthink these things.  I
needed to eliminate DC from my multiplier inputs, and back-to-back 47uF caps
did the trick admirably.  Moving on with my life.