Hardy, that is correct: no equalizer parts are needed for avalanche type
diodes like the 1N5408.
Each diode reaches a maximum reverse voltage determined by the individual
diode's. avalanche threshold voltage and the reverse current is limited by
lowest reverse current device in the string. They don't even need to be
matched.
Of course the sum of the diode reverse voltages has to be less than the
peak transformer voltages to keep the reverse current below a catastrophic
level. Your 12 diode string should be good for an 8 to 10KV power supply with
plenty of safety factor.
Forward current ratings need to be adjusted downward with capacitor filters
as the peak charging current can be 5 to 10 times average current. Power
loss heat is related to current squared and the individual diodes need
enough air flow to dissipate the added heat.
73,
Gerald K5GW
In a message dated 9/13/2013 12:16:10 P.M. Pacific Daylight Time,
n7rt@cox.net writes:
I have just rejoined the amp list after a few years and am wondering if
the diode equalization question was ever resolved.
I am building a new bridge HV PS and it uses 12 diodes per leg. Rich
Measures says using a .01 & 470K across each diode is no longer needed due to
improvements in semiconductor manf. processes.
I have 100 1N5408's that came off the same reel so I feel they should be
matched fairly close.
I would like to hear a few opinions.
Thanks
73 Hardy N7RT
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