This page presents various capacitor discharge power supply circuits for use with twin coil switch machine motors. Also shown are some optional wiring methods that can be used to enhance the availability and control of these supplies.
http://home.cogeco.ca/~rpaisley4/CDPSU.html
This circuit adds some capacitors and diodes to a traditional transformer type series regulator circuit to extend the normal operating range.
http://www.discovercircuits.com/DJ-Circuits/pwrboost.htm
AC signals can emanate from many sources, and many of these sources are incompatible with the most popular interface voltages, such as TTL.
http://www.edn.com/article/CA307868.html
This circuit may be used up to 40 volts.
http://www.jensen-transformers.com/as/as079.pdf