Hello John,

On Oct 05 10:24 in a msg to Russell Brooks, John Clarke of 3:713/730 wrote:

 JC> The main problem with them is that they take a few micro-Seconds to
 JC> fire during which time the over-voltage is presented to the
 JC> computer/modem etc.  The best systems have arrestors backed up by
 JC> high speed zener diodes (which react in nano-Seconds (1000th of a
 JC> micro-Second).  The zener operates first and holds the voltage down
 JC> until the arrestor has time to fire.

 JC> Another problem is that it is not easy to determine if the
 JC> arrestor/zener combination is till operational or has failed for
 JC> some reason.  If this has happened, and you don't know about it,
 JC> then you are no better off than having nothing at all.

 JC> Perhaps the best arrangement is to also include a series fuse that
 JC> blows when the arrestor operates.  This way you know when the
 JC> arrestor has fired since the equipment won't work until the fuse is
 JC> replaced.  At the same time the arrestor/zener combination could be
 JC> checked to see if healthy and replaced. 

Anything like that available? Or even the first, without the second.

Cheers,
Poe

--- timEd/2 1.10+