PIV at the rectifer was rated after measuring the voltage across the
choke, with two HV probes and a differential measurement. I remember
that it was about 2500 VAC, so thats why I had to use two caps. It
was, of course, sitting at high DC as well. It was near resonance, as
evident by very good regulation, load to no load (bleeder only). The
Q of the circuit was limited by the resistance of the choke and the
capacitors themselves I suppose. I would have to dig back through
papers to find the measurements, but it had a bandwidth of a few Hz,
probably simulated some AC with a power amplifier and generator to
drive it while biasing with some DC current. With a few Hz, out of
60, thats 30. Maybe it was less, I cannot remember. The point is,
this thing was not really driving to very high voltage, and sat at
2500 VAC worst case, for a 4500 VDC 1.1 Amp DC supply. So I had 12 -
15 kV PRV diodes.
This was over 15 years ago. But I would say hundreds of the rigs were
sold over 10 years, with this ciruit in them. I did it not so much
for dynamic regulation (class C FM - who cares!), but so that the no
load to full load reg was good (when folks would kill the driver
stage, i hated transmitters where the meter pegs off scale), and for
lower stored energy with still good filtering. It was a two section
LC filter with the first L resonant. Nothing over 6 Hy and 4 uF for
capacitors.
John
--
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|