[Amps] Equalising resistors with HV diodes

[R.Measures]

On Sep 21, 2004, at 1:23 AM, R.Measures wrote:

>
> On Sep 21, 2004, at 12:30 AM, peter.chadwick at Zarlink.Com wrote:
>
>>
>>
>>
>>
>> Rich's argument appears to me that because the current is the same in 
>> each
>> diode, and each diode goes into avalanche, the voltage distribution 
>> on any
>> one diode can't be such as to exceed the the reverse leakage current 
>> rating
>> of that diode.
>
> -  Only if the total PIV of the diode string exceeds the actual 
> voltage encountered on the job
> .
>> Now that leads to an interesting question: suppose you have
>> a 1 kV diode in series with a 200v diode, and that the capacitances 
>> are
>> equal.
>
> -  If the junction capacitance at 200v on one diode equals the 
> junction C of another diode at 1000v, the die of the 200v diode must 
> be much larger than that of the other diode.

Bzzzzzzzt.  I should have said ... ... the die of the 1000v diode must 
be much larger.

  Richard L. Measures, AG6K, 805.386.3734.  www.somis.org