K
krw@att.bizzzzzzzzzzzz
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On Thu, 08 Sep 2011 16:33:38 -0700, Rich Grise <richg@example.net.invalid>
wrote:
the appropriate application. I agree, using MOVs where a TVS should be used,
as you implied was the case at the PPoE, is dumb. The opposite is also true
(TVSs across the mains).
wrote:
No, I meant that TVS diodes and MOVs were two perfectly good components, inkrw@att.bizzzzzzzzzzzz wrote:
On Thu, 08 Sep 2011 13:01:42 -0700, Rich Grise <richg@example.net.invalid
wrote:
Gloria West wrote:
From what I've seen, avalanche rectifiers have waned in popularity -
giving ground to MOVs - which in their turn have stared to give way to
SIDACs.
MOVs generally have higher spike quenching capability than avalanche
and are less likely to fail S/C, they can however shatter and arc when
damaged by extreme surges.
Ian Field
Thanks, Ian, for the information. I did not know that MOVs can take the
place of avalanche dioces. I had a difficult time locating avalanche
diodes locally but MOVs I can find and have bought a few.
Ah. After a little clarification, it seems that what you're actually
looking for is a Transzorb:
http://www.vishay.com/diodes/protection-tvs-esd/trans-zorb/
Transorb is one trade name for a TVS diode. I use lots of 'em. They even
come in SC-70s, five per. ;-) They're especially useful if you can get
some
impedance in front of them. Also useful after a polyfuse.
I once worked at a place where they had MOVs all over the place -
MOVs have a soft breakdown curve, and they deteriorate a little bit
with each transient they suppress. When the company muckety-mucks
discovered Transzorbs, they issued ECOs to throw away all the MOVs
and replace them with Transzorbs.
Different component for a different purpose. I don't think I'd use a TVS
diode on the AC entry. ;-)
Nah, these were mostly on inputs of sensors used in a HV ultra-high vacuum
environment with various electron guns, ion guns, x-ray sources, and
secondary electron analyzers and all kinds of kewl stuff.
http://en.wikipedia.org/wiki/Auger_electron_spectroscopy
http://www.google.com/search?hl=en&q=cylindrical%20mirror%20analyzer
the appropriate application. I agree, using MOVs where a TVS should be used,
as you implied was the case at the PPoE, is dumb. The opposite is also true
(TVSs across the mains).
I was an Engineering Tech, my first job out of the USAF in 1977;
I arranged to get myself fired after my boss quit and they hired
the Fourth Stooge to replace him. ;-)
There's a lot of that going around.