[ARC5] Solid State --- diodes...and RFI

[Kenneth G. Gordon]

On 8 Feb 2018 at 15:38, Tom Lee wrote:

> Your analysis is spot on. Even "slow" rectifiers can have surprisingly 
> abrupt transitions from off to on (it's a phenomenon called reverse 
> recovery -- the diode stays on well after the voltage across it has 
> reversed polarity; when it finally does turn off, it does so with very 
> fast edges). The spectrum of the diode current looks like a remarkably 
> flat comb well past MF. Shunting that RF with a cap does an effective 
> job of knocking down the RFI.
> 
> Tom

That is very interesting to know, Dr. Tom. At the time, I was only guessing at the cause, but I 
did know that my "fix" worked. No more noise.

So, now I am wondering if paralleling modern diodes with a disk-ceramic cap is still a good 
idea?

I can see no bad effects for doing this, but I am not a professional at this sort of thing either, 
so I may be missing something.

Thanks again,

BTW, I am really a "belt and suspenders" type of technician anyway.

Ken W7EKB

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