On Nov 4, 11:17*am, JIMMIE wrote:
I came by what appears to be a power supply module from some old
military gear. It uses a synchronous vibrator unless my analysis of
the circuit it way off. My plan is to build a circuit to replace the
vibrator with a couple of power FETs driven by a 555 osc and a bridge
rectfier to handle rectification of the output. I was wondering if
there were any circuit designs around before I started to reinvent the
wheel. Also what freqency do they use. Seems like I heard 100Hz at one
time but I dont trust my memory on something I learned 40 years ago.
Any help would be much appreciate.

Jimmie

Hey OM:

Don't use a 555 use a TL494. A 555 has no control of the leading and
trailing edge of the so called square wave. /while one FET is going
off the other FET will come on. Towit the off time of most power FET's
is longer that the on time, thus the FET that you want to turn off
will still be on when the FET that you want on comes on thus for a
time both FET's will be on. Been there done that.

All you need is a power FET bridge, 4 FET drivers and the controller.

back in the day we used to make our own vibrator supplies , and now
with neo magnets out there I can keep the arcing down to nothing and
Suppressor diodes to keep the spikes down, the diodes and magnets they
didn't use back in the day 'cause they were to costly, all they could
use was buffer capacitors.

73 OM
de n8zu