baffled by ohm meter


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Old 07-30-14, 06:29 PM
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baffled by ohm meter

I have an ohm meter with a scale 200 2000 20k 200k 2000k
I have a resister I know is 27K
I have the meter on 200k and the display reads 26.6
so how do I get the resistor value of 27k
Shouldn't the meter scale read 1k so then I would multiply the 26.7 by 1000 and get my value
I dont get it?
 
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Old 07-30-14, 06:36 PM
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You set the meter to the scale just above the anticipated reading. If you don't know what to anticipate then you start at one end and work until you get a reading close to the middle of the scale.

I have the meter on 200k and the display reads 26.6K
So... 200K is the correct scale. Based on the tolerance of the resistor.... you could measure anywhere from 26.0K to 28.0K.

Resistors come in different tolerances. 1%, 2%, 5%, 10%, 20%.
The lower the tolerance the closer it will measure to it's intended value.

The following chart refers to resistors using four color bands with the fourth being the tolerance.

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Old 07-30-14, 06:40 PM
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I still dont get it isnt the 200k a multiplyer
how would I know the 26.7 is 26700
 
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Old 07-30-14, 06:47 PM
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When the meter is in the 200K setting.... the scale is 1-200K ohms. If the meter were in the 200 ohms setting it would be 1-200 ohms. In the 2000K scale it would be from 1-2000K ohms.

So yes.... there is a multiplier because your meter is probably labeled 1-200.
So in 200 ohms.. there is no multiplier.
In 2K ohms... it would be 10 (200x10=2000)
In 20K ohms... it would be 100 (200x100=20,000)
In 200K ohms... it would be 1000 (200x1000=200,000)
 
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Old 07-30-14, 06:51 PM
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ok thanks I understand that
But I think it would have being alot easier to make the 20k scale 1k and just multiply that by your reading instead of making it 20,000
Have a good night
Rick
 
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Old 07-30-14, 06:56 PM
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200k isn't a multiplyer...it's the max range for that scale. Digital meters are direct read for anything below the max on that scale. On an auto ranging meter, you have little M's and K's or nothing at all for resistance under 1K.

Your only math that needs to be done is when you really want megaohms for something that should be 1.5M (for instance) you'll have to convert 1500 (what it will show) on the 2000k scale, to 1.5 m'ohms.

This isn't like the old Simpson 260's or cheap meters that had a single graduated scale and a dial position of RX1, Rx10, RX100, etc.
 
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Old 07-30-14, 07:48 PM
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I guess I should have asked.... I just assumed an analog VOM.
 
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Old 07-30-14, 09:03 PM
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I don't think so, since he said
the display reads 26.6.
Most analog aren't that precise and don't have a display.
 
 

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