At 07:43 PM 2/2/00 -0800, Vic Rosenthal wrote:
>Larry Molitor wrote:
> >
> > So here's the question: why did the highly acclaimed 1N5408's fail?
>
>My theory is that a transient on the AC line is the cause. It was spread
>unevenly across the diode string because of junction-capacitance differences.
>Paralleling each diode with a low-tolerance .001 mf capacitor would have
>prevented this. I don't believe there is a need for equalizing resistors with
>modern diodes.
>
>There has been a lot of discussion on this subject here and a lot of strong
>opinions. I am not an engineer and am not speaking from authority; however, I
>haven't lost any diodes mysteriously since I started doing this (anecdotal
>evidence, not science).
>
>73,
>Vic, K2VCO
>Fresno CA
Vic,
Thanks for the observation. In my experience, I have never seen a
"mysterious" rectifier diode failure. Each time, the trail of debris
suggested turn-on transient or big-bang. I'll not rule out a line
transient, but in this case I don't think it's the culprit. I just wish I
had some better clues.
73,
Larry - W7IUV
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