[NLRS] Goof Proof Transverters

[Marciniak, Ed]

You can go one better than that and use a transient absorber (basically a zener diode with a breakdown voltage above what may be supplied to the equipment normall) with a fuse. The transorb when subjected to a reverse supply becomes a forward biased diode.....
For 50 cents or so, you get overvoltage and reverse polarity protection. The upside: no voltage drop, and overvolate protect. The downside....replace a fuse, which with Murphy's law won't be convenienly available and possibly the diode itself if the fuse doesn't blow fast enough

----- Original Message -----
From: nlrs-bounces at mailman.qth.net <nlrs-bounces at mailman.qth.net>
To: nlrs at mailman.qth.net <nlrs at mailman.qth.net>
Sent: Sat Aug 14 21:31:54 2010
Subject: [NLRS] Goof Proof Transverters



 A simple, low cost method of protecting medium power electronics equipment
from reverse polarity connections is to simply connect a silicon diode
across the equipment side of the protection fuse.  Use a diode with an
ampere rating perhaps 1.5 to 2 X the rating of the fuse.  The cathode of the
diode goes to the plus 12 V equipment side of the fuse and the anode goes to
the negative which is usually ground.  Upon connecting the power source in
error the diode will conduct and blow the fuse.  A 3 amp diode could be used
in conjunction with a 1 or 2 amp fuse, a 6 amp diode with a 3, 4, or 5 amp
fuse.  This method does not result in any voltage reduction to the
equipment.

 

73  Rex K0KP EN36vw

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