[Amps] .01uf caps across diodes ?

[Steve Thompson]

As I understand it, the diode doesn't go low resistance when it 
avalanches, it's more like the characteristic we associate with a zener 
type diode so it maintains its own particular breakdown voltage while 
conducting - obviously within limits.

Steve G8GSQ

On 14/12/2022 00:52, Ron W4BIN wrote:
>     MU 4CX250B wrote:
> 
>> An interesting point, Steve. If I understand you, you’re saying that
>> if a modern diode in a series string approaches reverse breakdown, it
>> will start to conduct, thus shifting its overload voltage to other
>> diodes in the string. Before the advent of controlled avalanche
>> diodes, however, an overloaded diode would just short circuit, thus
>> permanently shifting its voltage to the remaining diodes in the
>> string. This process, once started, would likely lead to the
>> destruction of the entire string.  To me, the takeaway message is that
> 
>    No that has never been the case, "controlled avalanche diodes" of a
> particular type all avalanche at the same Voltage.*
> Otherwise the lowest reverse Voltage device could avalanche and present a
> very low resistance, (causing an increase in reverse Voltage across the 
> rest)
> then the next lowest Voltage device could avalanche until they would all
> avalanche at which time, the current would destroy most until one "blows 
> open"
> ending the catastrophe.
> 
>    Zener diodes below about 6.2 Volts are true Zener diodes, above about 
> 6.8
> Volts are "controlled avalanche diodes" and as long as they are conducting
> reverse current less than Imax they are not harmed.
> 
>   * in our high Voltage operations a tighter grouping of avalanche Voltages
> can be maintained by buying in lots like of 50 or 100 and keeping the
> batches separate and constructing strings all from the same batch.
> 
>> there’s little to be gained these days by adding .01uF caps to each
>> diode. This is a helpful explanation, Steve. Thanks!
>