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Old 09-07-2012, 17:12   #1
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ohm reading

when i use my digital multimeter and set it on ohms, check between two points, it will read either ohms or milli-ohms. which reading has the least resistance. i generally use my ohm-meter for continuity checking and was curious the difference between the two readings.
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Old 09-07-2012, 18:10   #2
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Re: ohm reading

Low resistance circuits should be measured with a milli-ohmmetr.
A "decent" connection should have a resistance of less than ±0.1 ohms (or 100 milli-ohms).
The operation of an Ohm-Meter is based on the standard technique:
Pass a known fixed current through the known resistance, and measure the potential
drop across it.
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Old 09-07-2012, 19:48   #3
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Re: ohm reading

Are you sure it's not mega ohms? A typical meter will have Ohms, K Ohms (1000 ohms) and M Ohms (1,000,000 ohms). A milli ohms would be 1/1000 of an ohm.
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Old 11-07-2012, 04:24   #4
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Re: ohm reading

this is exactly why i'm confused. i use to have a meter that you had to sellect the ohm setting. that's what i can't figure out which one should be used for what.
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Old 11-07-2012, 04:59   #5
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Re: ohm reading

A MegOhmmeter (or “Megger”) is typically used for measuring insulation values, resulting in very large ohmic readings (high resistance).

A MilliOhmmeter is typically used for measuring connection values, resulting in very small ohmic readings (low resistance).
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Old 11-07-2012, 06:59   #6
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Re: ohm reading

milli ohms measures smaller resistance, than ohms, like mms and kilometres!!
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Old 11-07-2012, 07:28   #7
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Re: ohm reading

sounds like you have a modern auto range ohm meter. It selects the range based on the value of the reading that it measures. There's a 1000 milli ohms per ohm....
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Old 11-07-2012, 10:32   #8
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Re: ohm reading

I was using an auto ranging meter to check the lighting connectors and wiring on my boat. I continued to be confused as to whether I had a good connection or not, until I got a piezo buzzer and some alligator clips at radio shack. I had a good connection when I could hear a beep, connecting one side to the battery the other to the connector. Now as Gordy may say even a beep in this system doesn't indicate a good high current connection.
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Old 12-07-2012, 01:35   #9
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Re: ohm reading

I think twistedtree is correct , the average multimrter that I have seen doesn't usually have a milliohm scale , it will read .x of an ohm which can be calculated in miliohms but unless it is a quality meter it won't be very accurate on low ohms. M ohms is usually meg ohms [ high resistance ] most multimeters read megohms . Hold the probes one in each hand and you will get a reading through your body that will be megohms , don't do this with a insulation tester aka megger or you will get a 500 [or more ] volt dc shock. What is the brand and model of your meter ?
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