Date:         Wed, 26 Feb 2014 16:13:01 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Volt Ohm Meter: Continuity Checking, Ohm Range Settings
Comments: To: Neil N <musomuso@GMAIL.COM>
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              mail.com>
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At 03:28 PM 2/26/2014, Neil N wrote:
>I'm measuring continuity to track down where I connected a + wire.
>With battery DISconnected, digital meter @ 200 Ohm range, no
>continuity seen (displays a 1). At 2000 Ohms (diode test setting): ~
>1700 Ohms. As I increase Ohm range, the decimal point moves, then at
>20M Ohm range, I see 0.00.
>
>At the highest range, am I seeing a false reading for continuity?

You're seeing a consistent (and presumably correct within the meter
spec) reading for resistance.  1700 ohms is 0.001700 megohms.  You're
seeing the first three digits which are 0.00.  All correct.

Whether 1700 ohms represents continuity for your purposes depends on
what you're trying to do.  If you're measuring a wire of normal
proportions the usual reading on your ohmmeter would be the minimum
it can display (typically shows up as a few tenths of an ohm, same
reading you'll get if you touch the two leads together.  If you
really need to know what those low resistances are you can a) spend a
fortune plus time learning about it on a *much* fancier ohmmeter; or
b) do what we normally do which is to pass a normal load current
through the wire, measure the voltage drop across it which will be
some number of millivolts, and calculate using milliohms = millivolts / amps.

But for tracking whether there's a basic connection, the 200 ohm
range of the meter will do fine, or the continuity beeper which is
usually set to trigger at somewhere between about 50 and 150 ohms
(see your meter specs).

Yrs,
d