Thread: Multimeter Ohms
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Dave Martindale Dave Martindale is offline
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Default Multimeter Ohms

Peetie Dot Wheatstraw at Gmail Dot Com writes:

In other words, the number is the actual resistance in numbers and you have
to place the decimal point in the correct place.


If I have to place the decimal point, the reported number is -not-
the "actual resistance in numbers".


The scale setting and display are completely consistent. You have the
meter set to the 2k ohms scale, and the largest (non-overrange)
displayed value will be 1.999 k ohms. If you want the result in ohms,
and not k ohms, you need to do the conversion by yourself.

Similarly, if it had a 200 ohm scale, the decimal place would be one
from the right, so the largest display would be 199.9, and the result is
read as ohms directly. If it had a 2 Mohm scale, the decimal place
would be one in from the left, and the largest reading is 1.999 M ohms.
Again, you have to convert from Mohms to ohms if you want that.

The only difference with really expensive meters is they may have a
scale indicator in the display, so you can read whether the units are
ohms or K ohms or M ohms on the display. That's necessary for an
auto-ranging meter, but for a manual meter you ought to know what range
you set it to.

The reported # is a scaled #. Scaled by 1000. When the scale setting
on the MM device is 2000.


The reported number is in k ohms - as you'd expect from the scale you
chose.

The next highest setting is 200k ohms. If I measured resistance on the
same circuit, precisely what would it report? I'd test it but the
circuits are now installed where I can't get to 'em.


Now the decimal place has moved 2 positions to the right to make the
largest display 199.9 kohms. 500 ohms is still 0.5 kohms, so your meter
would display 0.5 on this range - correct, but not much precision.

Dave