Got a Radio Shack 22-221 which I have separated from its instructions. Anyone tell me how you calibrate the ohmmeter function?
Thanks
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“Where will our children find their enjoyment when everything gets itself done by steam? Frederick Law Olmsted, 1850s. “
Replies
The owner's manual is available on the Radio Shack website:
http://support.radioshack.com/productinfo/DocumentResults.asp?sku_id=22-221&Name=Meters%20and%20Scopes&Reuse=N
Follow these steps to measure resistance.
1. Disconnect power from the circuit you are testing.
2. Set the function selector to one of the OHMS positions.
3. Touch the probes together and turn OHMS ADJUST to bring the pointer to
the "0" position on the scale.
4. Touch the probes across the circuit or component you are testing, and
read the results on the scale.
Edited 5/22/2008 6:08 pm by Stuart
See, I knew there'd be something really simple I was missing. I skipped right to the google and dogpile searches and that didn't show up.Thanks much,
Ken++++++++++++++++++
"Where will our children find their enjoyment when everything gets itself done by steam? Frederick Law Olmsted, 1850s.
"
Stuart gave you good instructions for _zeroing_ the ohms scale, and if that is what you want to do, his directions are OK. But zeroing the meter scale is just one part of calibration. To _calibrate_ the ohms function, you'll need to measure at least one known resistance in each range and see if it reads correctly on the meter scale.
You're right about calibration but most inexpensive meters don't have provisions to adjust it. I just cut and pasted that from the Radio Shack instruction book for his meter.
Actually, in my experience even good quality handheld meters can be a little iffy if you want exact results for resistance measurements - you have to make sure the leads are in good condition and plugged in well (I have a nice Fluke, and when shorting the leads together it'll read anywhere from 0.1 to 10.0 ohms if I wiggle the lead connectors around.) A lab quality four wire meter is probably a better choice if you need to make precise measurements.
I've not seen that particular RS model and it sounds like one of the analog meter types with the zero on the front dial. But if somebody were to open it up, put a screwdriver to a pot labeled "ohms adjust" and use that to set the pointer to zero, they might get some strange readings.
It's an analog type with an adjustment wheel to "zero". That's what I was looking.works great now, for what the price I paid. Works even better when I replaced the new battery with a good, new battery. Probably wouldn've had to ask if the battery had been good.++++++++++++++++++
"Where will our children find their enjoyment when everything gets itself done by steam? Frederick Law Olmsted, 1850s.
"