This circuit uses a novel
approach to produce a fully isolated and regulated 5 volts @30ma from the 120vac
power line. It uses two tiny SCRs that alternately discharge two capacitors through
a miniature high frequency transformer. The voltage spikes produced through the
transformer are rectified, filtered and regulated. A very common 8 ohm audio
impedance matching transformer can be used for the transformer.
Published in EDN, Feb.17, 1992