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Re: [Amps] Semtech?

To: amps@contesting.com
Subject: Re: [Amps] Semtech?
From: W0UN -- John Brosnahan <shr@swtexas.net>
Date: Mon, 25 Oct 2004 10:06:32 -0500
List-post: <mailto:amps@contesting.com>
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At 09:46 AM 10/25/2004, you wrote:
Hi Richard,

Can you tell me the technical explanation (in an "Idiot's guide to" method) as
to why a conventional diode tester (that shows .6xx voltage across an ordinary
silicon diode) will not show any indication across these diodes? Are they not
just plain old standard diodes? What's inside the modules? Just curious... and
I bet you've "been there, done that"?

Thanks, -Web

It is a large stack of diodes--each with a .6 or .7 volt drop. So the SUM of the drops can end up being anywhere from about 6 to 10 volts. So a normal VOM does not have enough battery voltage to overcome the total drop and shows "open" in both directions. Some of the older VTVMs had more voltage and could possibly test these "string-of-diode" modules. But current, low-power, VOMs will usually not.

--John


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