20 Mar
2007
20 Mar
'07
9:37 a.m.
On 20 Mar 2007 at 3:48, Mr Ian Primus wrote:
So - in replacing this component, what should I be
looking for? The only specification givin is 100A, but
I see varistors in various places rated in terms of
Joules or Volts. I don't want to replace the varistor,
only to have it not give me any protection for that
transistor.
Well, you know that this is either a 20 ma or 60 ma current loop
setup, so why not use Ohm's law and compute what the voltage at that
point should be, then add some for a safely margin, say, 50% and
select the varistor accordingly?
Cheers,
Chuck