I...built a charge pump like this, viewed in a fixed font:

0.047 uF @400 V
|| |
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|| | | |
| | 3V
120 VAC --- --- to clock
^ _
0.047 uF @400 V | |
|| | |
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||

Nick (nicksanspam @ ece.villanova.edu)

Caps do have a failure mode,
so a series safety R is normally included with these type circuits.
NT (meow2222 @ care2.com)

It should be noted that such *series capacitor* devices
were outlawed for commercial products long ago in Europe.
As the Big Cat notes, without a resistor to limit things,
failures are usually dramatic.