# Fun with a mutimeter

DrClapeyron
So I just bought a digital multimeter, plugged it into a trailer outlet and that's been about it. When I get off work in the coming weeks I'll use it on my car. So I ask, are there any fun things to do with a multimeter?

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I've been an EE student for four years...and I still can't think of a good answer.

connect yourself to a 12V battery and measure the current through your body.

measure the magnetic induction from waving spinning a strong magnet in a coil of some wire.

test the purity of water by measuring the current across two ends of an insulated cup

russ_watters
Mentor
Measure the voltage of every battery in your house and sort them in order of greatest to least voltage. Discard any that are below their nominal voltage.

Chi Meson
Homework Helper
Get a piece of copper and a piece of zinc, and measure the currents that flow between them when you stick them into different types of fruit.

whee

ideasrule
Homework Helper
Take two metals, connect them, heat the junction, and marvel at the thermoelectric effect. I always found it weird that just heating metal could produce a voltage.

If you have a budget, buy some logic gates and design some cool electric circuits. Electronic components are dirt cheap--in my hometown, there's a surplus store that sells resistors, capacitors, LEDs, gates, etc. by the kilogram.

Averagesupernova
Gold Member
Get everyone in your house to grab the leads (one in each hand) and see who is the best conductor.
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Hook the leads (AC amps mode if it has this mode, otherwise AC volts) to a loudspeaker and see who can get the meter to read the highest by yelling into the speaker.
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Ummmmm, that's all I can think of now.

Measure the voltage of every battery in your house and sort them in order of greatest to least voltage. Discard any that are below their nominal voltage.
Sounds like a fun weekend yeah?

If you have a budget, buy some logic gates and design some cool electric circuits. Electronic components are dirt cheap--in my hometown, there's a surplus store that sells resistors, capacitors, LEDs, gates, etc. by the kilogram.
So jealous. My old town has a store like this, but I don't live there anymore.

You could measure the resistance of soup as a function of saltiness.

turbo
Gold Member
Buy an alligator clamp that fits one of your probes, and use a sacrificial conductor (a common nail will do). Pop all the battery-cell caps off your car battery, and measure from one pole (doesn't matter which) to the acid solution in each cell. If you have less than a 3V difference cell-to-cell, look out. If you have a battery that's about ready to go south on you, this will pick it up most of the time.

MATLABdude
Measure the resistance between various body parts? Then figure out how much current would go through you at 120/240 V (or whatever the mains is where you live), and compare that to values found below:
http://www.medtek.ki.se/medicaldevi...resholds for effects of electric current.html
http://en.wikipedia.org/wiki/Electric_shock#Body_resistance

I had a textbook once that described the effect that various currents going through the heart (as opposed to through the body and/or around the heart) would have, ranging from tingle, to fibrillation, to arrest, and then burning, but don't remember the values off hand.

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Bust out some rockin' beep jams on the connectivity tester! :D

Here's a fun one: Stick the two probes into the ends of a pool of distilled water, and observe the resistance. Now submerge the multimeter and observe how the resistance of the water decreases as free ions from the multimeter's internal circuity are added to the solution.

13 years ago I bought one as a circuit tester.. figured I'd get more use out of it than that....

Nope

Here's a fun one: Stick the two probes into the ends of a pool of distilled water, and observe the resistance. Now submerge the multimeter and observe how the resistance of the water decreases as free ions from the multimeter's internal circuity are added to the solution.
I sure as hell wouldn't do that with my multimeter.

Do not submerge any electronics you want to keep in water unless they are waterpoofed, even if it is distilled water.

Also, I don't believe your account makes a lot of sense.

Measure static electricity.
Have you ever combed your hair really fast with the back of a plastic ball-pen and used it to attract small pieces of papers. Well I guess you had done that. But you could never tell they had either positive charge or negative charge.
Now that you got the almighty digital multimeter you can tell. Just put the meter in voltage mode (miliVoltage mode, if there is such options) and let the two probes floating. You may get a few milivolts in air. Now comb the pen and bring it near one of the probes. You will see the changes. Draw your conclusions then!

No.

Seriously, one who follows your instructions is very likely to break their multimeter.

umm lol.. not my instructions.. and I'm pretty sure King was being intentionally silly..

umm lol.. not my instructions..
one of you contribute to PF so you can have an avatar and I can tell you apart.
I'm pretty sure King was being intentionally silly..
That seems likely, but people have weird beliefs about distilled water, it has elements of plausibility enough that someone might actually try it.

one of you contribute to PF so you can have an avatar and I can tell you apart.
Avatar uploaded, but isn't showing yet....
Now you can tell us apart

MATLABdude
Bust out some rockin' beep jams on the connectivity tester! :D
Make like Data and bust some moves at the same time:

OMG that's priceless lol

Chi Meson