+12V Voltage Doubler
This
circuit was originally designed to operate a 15 volt regulator from an unregulated 12 volt
AC adapter, but can be used for whenever you need more than 12 volts from a 12 volt
supply. I’m posting it because one reader built a 12 volt DC to AC converter that I had
posted and noticed that he did not get 12VAC out. That isn’t possible with 12 volts input
to that circuit because the peak voltage needed would be 17 volts. This circuit will solve
that problem.
D2 and D3 may be 1N4004 or
better. Schottky barrier diodes will raise the output voltage by a volt or so. This
circuit is not regulated. You will get twice the input voltage minus about 2 volts,
depending on load. This circuit worked well delivering about 250ma in a prototype to a
commercial product I developed. A more appropriate transformer was used in
production, eliminating the need for this converter. |