> I tested some 1N5408s which started leaking a few uA at just
> under 3kV. This made me think - without added resistors or
> capacitors, the voltage sharing along a string in reverse
> bias will likely rely on the capacitances of the diodes.
> Lower capacitance takes higher voltage, and the varactor
> effect pushes the capacitance lower and so on (and the
> reverse on the rest of the string) - you could end up with
> some VERY uneven sharing. If the diodes have catastrophic
> reverse breakdown you get domino effect. Controlled
> breakdown alleviates the effect, shunt components avoid it
> but deal you a different set of potential problems.
>
> Steve
That's basically what the semiconductor engineer at Motorola told
me also. He said the biggest problems was uneven reverse
recovery times, even with diodes from the same source.
73, Tom W8JI
w8ji@contesting.com
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