Science Buddies: "Ask an Expert"

Hi!

I’m helping my 5th grader with a fruit battery experiment where we are testing different foods for voltage, current and resistance, but I’m not good at reading the amps and resistance on our multimeter.

Can anyone please tell me how to write out these readings? Thanks in advance!!

SarahMK - The photos are helpful, but the meter is a bit confusing. It appears to be an auto-ranging type but the readings on the display are confusing. You did determine that there is a "COM" - black connection on the meter, but 3 others depending on the value to be measured, a) 10 Amp high current, b) mA medium current, and c) a general input for volts, ohms, Hz etc. In photo's 1 and 3, you are measuring current and the display seems to be correct in measuring 61,1 uA on the first photo and 653 uA on the 3rd. I'm very confused by the resistance measurement in photo 2. It appears that you have the test leads in the correct socket, but the display seems to indicates 'volts' instead of 'ohms'. That's very confusing. The ohmmeter seems to also test diode conduction as well. I recommend trying to 'borrow' a more conventional multimeter from a friend or the school for more confident readings.

Rick Marz

Thanks Rick,

Yes! Very confused. The uA kept switching decimal places maybe to mA without me noting the symbol change?

Also instructions for Ohms said to switch the function button because Ohms read 0. So I don’t even know what unit that is.

Boy thank you for the suggestion.

Hi SarahMK,

Just chiming in in case you haven't seen it, we have a very extensive multimeter tutorial that may help: https://www.sciencebuddies.org/science- ... multimeter