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Extech EX330 current ranging issues
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Extech EX330 current ranging issues

by bebo on Wed Oct 17, 2018 11:09 pm

I'm getting some results from the multimeter that seem wrong. When I switch between microamps and milliamps, the decimal point only shifts one place. A reading of 15 microamps reads as 1.5 milliamps when I switch the setting. That and the value seems totally off for a simple series resistor circuit. 9VDC and two 1K resistors in series should be 4.5 milliamps, correct? On the microamp setting, I can toggle the "range" button and get two different values, 13.3 and 40. What gives?

bebo
 
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Re: Extech EX330 current ranging issues

by adafruit_support_mike on Wed Oct 17, 2018 11:22 pm

Could you post a photo showing the connections you're using when you take the measurements please? 800x600 images usually work best.

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Re: Extech EX330 current ranging issues

by bebo on Thu Oct 18, 2018 7:33 am

I'll get an image shortly, but when I made the same measurement with a different, lower quality meter, it reads 4.5mA just like it should.

bebo
 
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Re: Extech EX330 current ranging issues

by bebo on Thu Oct 18, 2018 7:50 am

I have the meter attached between the 9V rail and the first 1K resistor. The Woods meter is in agreement with Ohm's law, the Extech not so much. If I switch to the 5V rail, the Woods reads 2.5 mA, and the Extech 1.7 mA.
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bebo
 
Posts: 56
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Re: Extech EX330 current ranging issues

by adafruit_support_mike on Fri Oct 19, 2018 3:56 am

Thank you.. the circuit and connections look good.

Do you get weird values on any of the other settings?

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