[AMPS] glitch resistors

OZ5IQ oz5iq@teliamail.dk
Sat, 8 Sep 2001 15:20:14 +0200




HI Tom, W8JI and the group

TNX for your answer to my comment. Always gd to have tech. discussions. HI    Just think of how we would have been IF we always have been listening to our old ones. but to your comment

>> I Always put those current limiting devices at the LOW voltage
>> potential.


RE:
>
>That's not a solution I'm afraid.

Well you shold NOT be - and of the following reasons:

>When you have an arc, the resistor MUST be able to handle the full 
>supply voltage across the terminals of the resistor no matter where 
>it is located in the path.

Thats not correct - why you forget the selfinduction in the trafo !  How do you think it behaves for lets say  even  1mS arc ?  Yes, the rise in voltage will NEVER travel through the trafo, why the "pulse" is at that short time  !!    You may transfer pulses at longer period yes, but not that short - they will "die" relatively short time after entering the trafo.

>That is why you always need a suitable HV resistor, even if you 
>place it in the negative rail....which is a terrible place to put it 
>anyway because it is bypassed by all the stray C in the power 
>supply and requires the negative rail to lift to supply potential in 
>order to limit current!
AGN. 
remember the transfer speed capability of a trafo.
its another thing when talking ferrite trafoes - you may be right.

So - yes theres an easy way out !

All the best  from Denmark   and  VY 73 tnx input  de   OZ5IQ, Kim





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