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From: mberns@cygnet.UUCP (Mike Bernstein)
Newsgroups: sci.electronics
Subject: Re: How to save your car's electrical stuff?
Message-ID: <1724@cygnet.UUCP>
Date: 28 Nov 89 15:03:13 GMT
References: <6709@merlin.usc.edu>
Reply-To: mberns@cygnet.UUCP (Mike Bernstein)
Distribution: usa
Organization: Cygnet Systems -- Sunnyvale, California
Lines: 9


 Please excuse my lack of a diagram but if you want to buld a circuit to 
blow a high current fuse at a specific overvoltage it will work a lot 
better to use an SCR triggered by the zener.  A very small SCR can blow
a 30 amp fuse.  You wil need a very big Zener, as overvoltage problems
will tend to creep up on you and melt the zener.  Also a 15V zener is 
too low.  Keeping tolerances and temperature variations in mind a threshold
of at least 17 volts is required.  I can't draw the circuit but I will
email a futurenet DASH4 file of it to anyone interested.


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