Olin Lathrop wrote

> Take the TVS that measured open with the ohmmeter and put a 1Kohm resistor
> in series with it.  Now connect a variable power supply to the combination
> and monitor the voltage accross the TVS.  At some point the TVS voltage 
> will
> stay roughly flat as you increase the power supply voltage.

Thanks for that suggestion Olin, I went straight out to the w/shop to try it 
out.

As frustrating as it is, the device appears open circuit both ways. I fitted 
a 1K ohm resistor in series and ran the supply slowly up to 50 volts, and 
the voltage across the device went straight up to 50V too!! Tried it the 
other way too and same thing.

I hooked up the other one, and that acted just like a 195 ohm resistor, both 
ways, so I'm pretty definite that one is dud.


> Power dissipation is mostly a function of the package, so if the 
> replacement
> has the same voltage rating and the same package, then it should be 
> roughly
> equivalent.  Since one of the existing TVSs blew out, it wouldn't hurt to
> replace both with a slightly bigger part, since that should take a little
> more energy before frying.

That sounds pretty much how I normally work when I cant find a circuit or 
any documentation to help. I normally get away with it, but thought it was 
definitely worth a try asking all you guys.

Thanks again,   Roger


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