Nicely explained in the 2010 ARRL Handbook 7.7.4. You want fast
recovery diodes. Of course, fast recovery (50 ns), while it reduces
the reverse-bias energy per cycle, may still mean lots of HF
73 Martin AA6E
On Tue, Jan 12, 2010 at 12:04 PM, Jim Brown <email@example.com> wrote:
> On Tue, 12 Jan 2010 11:22:26 -0500, Paul Christensen wrote:
>>> "...The mechanism that causes all of that noise is the rectifier diodes.
>>> If you use diodes that have a long minority carrier lifetime, no problem,
>>> but with the faster diodes that are being used nowadays..."
>>That's a new one on me.
> To the extent that "faster diodes" shorten the rise time of the waveform,
> that makes some sense. Another primary mechanism is a current loop that is
> physically large, thus generating a strong magnetic field. A third mechanism
> is a "pin 1-like problem" with external wiring that puts noise on that
> wiring as a common mode signal. The capacitors across the diodes suggested
> in the reference are essentially reducing the HF current that excites these
> FWIW, I don't find the cited reference all that wonderful. On the other
> hand, there's an excellent treatment of RFI in switching power supplies in
> Henry Ott's latest book, the third edition of what has been "the EMC bible"
> since its initial publication in 1976.
> Jim Brown K9YC
> RFI mailing list
Dr. Martin S. Ewing, AA6E
Member IEEE, URSI, AAS, ARRL
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