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From: peterb%harvard.uucp%Seismo@pbear.UUCP
Newsgroups: net.ham-radio
Subject: MOV transient protectors
Message-ID: <8553@brl-tgr.ARPA>
Date: Sat, 23-Feb-85 14:50:38 EST
Article-I.D.: brl-tgr.8553
Posted: Sat Feb 23 14:50:38 1985
Date-Received: Wed, 27-Feb-85 05:49:38 EST
Sender: news@brl-tgr.ARPA
Lines: 51

Most MOVs are designated both by peak current and NOMINAL voltage
These devices work for both AC and DC. (AC devices will last longer
though).

If you hooked up MOVs at the feed box for the house, it would protect
from the outside disturbances, but not inside transients.

If you want to protect logic, I recommend tranzorb devices by GS
(general semiconductor), specifically the

	1N5908

This devices charecteristics are:

	1.5Kw Peak Pulse Power dissipation @ 25 deg c
	Tclamp (0 V to BVmin) < 1 pecoseconds! (theoretical)
		(can not measure it if < 3 picoseconds)
	Forward Surge rating (1/2 cycle):
		200amps, 1/120 second @ 25 deg c
	Steady State power dissipation:
		5W @ 75 deg c, lead length 3/8 inch
	Repitition rate (duty cycle):
		.05%

It comes in a molded case, (9.4mm X 5.08mm)

Clamping voltage is 7.2 volts, and rises only slightly to ~ 8 volts @
100v and rises slightly beyond. This is unlike MOVs that may rise to
quite higher than the nominal voltage indicated.

10Kpf capacitance, reducable to 200pf by schottky diode in series, 1KA
@ 7.2 V

This is only one of the devices GS makes, and this is intended for
logic protection. Originally designed for MIL work to protect from
nuke EMP, these devices work quite well.

for more info, write GS for a catalog:

	General Semiconductor Industries, Inc.
	2001 West Tenth Place
	Tempe, Arizona 85281
	(602) 968-3101

This is not an endorsment of mine, however, a friend does endorse
them.

				Peter Barada
				ima!pbear!peterb

PS      cost of that little gem is about 75 cents!