Your explanation about NOT using capacitors with UF diodes is -- by the way -- consistent with something I had read in Merlin Blencowe's book on power supplies, but I now understand it better thanks to your explanation.teemuk wrote: ....Such diodes [ultra-fast recovery types] absolutely should not have capacitors connected in parallel because it detriments their operation.
If you slow down diode's operation with a parallel capacitor the ringing frequency of the resonant circuit decreases and the result is that the noise isn't as easily radiated around and picked up by surrounding circuitry. The magnitude of the transients may also decrease. This trick works well with diodes that have slow reverse recovery times.
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Fork in the road: The current power supply ( a 2-diode voltage doubler circuit) uses old (standard?) diodes with a .0022uF cap across each diode -- I was going to just stay consistent to that original design -- but replace the diodes and capacitors. It is beyond my expertise to specifically dial-in the capacitor value, so I was just assuming that new .0022uF caps and new (I was going to use 1N5408) diodes would do the trick.....?
The other "road to take" would be UF5408 diodes and skip on the paralleled caps....I guess.....?
Without being able to put this thing on a scope and really hash it out, is one approach more *forgiving* to a beginner than the other?
Thanks very much for the assistance!
