Re: transformerless high-voltage supply

[John Denker <jsd@MONMOUTH.COM>]

At 09:40 AM 12/7/00 -0500, Michael Edmiston wrote:
> I thought of an interesting type of DC-to-DC step-up "power-supply" that
> helps explain how this can be done, and it is an example that is pretty
> simple to understand.
>
> Let's assume I charge all four batteries at once (charging in parallel
> from a 1.5-volt supply) then I use them in my camera (in series to provide
> 6 volts).

One can easily go beyond rearranging batteries by hand, all the way to a
real-life Cockcroft-Walton voltage multiplier.
  http://home.earthlink.net/~jimlux/hv/cw1.htm

Advantages of this include:
 * It is pretty simple to understand.  If you understand diodes and
capacitors, you can understand this circuit.
 * It is nevertheless a clever circuit.
 * It is part of the patrimony of physics:
   http://www.nobel.se/physics/laureates/1951/cockcroft-bio.html
   http://www.nobel.se/physics/laureates/1951/walton-bio.html
 * It remains a practical circuit to this day.  It scales to really high
voltage better than a transformer or inductor, and scales to really high
current better than a Van de Graaff or pelletron.  I remember seeing one of
these things that put out something like 1,000,000 volts at 1 amp;  it was
used for specialty welding.