Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!ncar!husc6!bloom-beacon!mgm.mit.edu!wolfgang
From: wolfgang@mgm.mit.edu (Wolfgang Rupprecht)
Newsgroups: sci.electronics
Subject: Re: ZZZZAAAAPPPP!!!
Message-ID: <5790@bloom-beacon.MIT.EDU>
Date: 15 Jun 88 23:07:25 GMT
References: <517@amc-vlsi.UUCP>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: wolfgang@mgm.mit.edu.UUCP (Wolfgang Rupprecht)
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Organization: Freelance Software Consultant, Boston, Ma.
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In article <517@amc-vlsi.UUCP> dale@amc-vlsi.UUCP (Dale Wlasitz) writes:
>I am curious about the effects of EMP on electronic systems in
>general. What can be done to minimize damage to electronic circuitry?
>What components/subsystems etc. are most susceptable (sp?) to EMP.
>What are typical pulse durations and peak amplitudes? Obviously smaller
>scale lab experiments have been conducted. What are the effects on
>us humans in the same vicinity as the damaged electronics?

Well, I guess this posting can be a test of sorts.  Lets see if our 
friends at tycho.ARPA are still on usenet... 

This information comes from "Compliance Engineering 1988" Wellesley
Press, Framingham Ma. pages 316-322.

The peak voltage of a "typical" (???) EMP wave is 50kV/m with a rise
time of ~10 nS (10-8 S) and a fall time of ~1 mS (10-6).  The total
energy received is only about 0.6 J/m**2.  The electric field strength
remains fairly constant in the 10khz to 1Mhz band.  It decreases by a
factor of 100:1 in the 1Mhz to 100Mhz band.  It continues to decrease
faster for frequencies greater than 100Mhz.  Most of the energy is
between 100khz and 10Mhz.  99% of the energy is below 100Mhz.

Obviously you can shield from this is by 1) having a fairly high
integrity ground/shielding system 2) use low-pass filtering 3) use
diode clamps to +/- power supplies and user MOV's to clamp those
supplies themselves.

The EMP simulator mentioned in this article uses HV capacitors
discharged through spark gaps. (This is probably only good for a small
zap.)

Some references from the same article:

Bodson, D., "Electromagnetic Pulse and the Radio Amateur," QST August
1986 pg. 15.

Elgal Corp., "Systems for EMP Simulation and RFI Material Testing,"
published by AR, 160 School House Road, Souderton, PA 18964-9990

Goldstein, C. and Tehori A., "A Small Parallel Plate System for EMP
Simulation".   IEEE EMC Symposium 1987 pg. 135

--
Wolfgang Rupprecht	ARPA:  wolfgang@mgm.mit.edu (IP 18.82.0.114)
TEL: (617) 267-4365	UUCP:  mit-eddie!mgm.mit.edu!wolfgang