finding out the amp usage of a part

Question

hi sounds like quite a beginner question but I need to find out how much ma a device is using

as I'm having some trouble getting some components to work together through a power supply i have looked on the multimeter but can't seem to locate what i need and where on the component i need to add this to

the component in question is a peltier that i believe is 12v but due to it being sealed in a part i can not see

any advice would be great

many thanks

shane

michaelwylie · Accepted Answer

You need a multimeter that measures current. Disconnect the power supply line going to the Peltier Cooler and insert the multimeter in series with the Peltier cooler. Some multimeters do not measure current, so your may not be able to. Having said that, it is a fairly common measurement and most multimeters do have the ability to measure current. Have a look at this multimeter: http://www.newark.com/fluke/fluke-87-5/digital-multimeter-dmm-handheld/dp/96H6287 You can see there are four ports on the bottom. One is ground or common, one is for voltage or resistance measurements, the other two are for different scales of current measurement. Follow this:

supper_slash · Answer

Another way is by measuring resistance, and doing some math. Someone corect me if i am wrong, it has been a while sence i took my law exam, but. If you put your meter into the ohm setting, and with no power on, and the device unhooked from other circuts, take the two meter probes and get a reading of the ohms that it has. than using the middle formula, Take your voltage, (12) I am guessing and divide that into the Resistance (50) " Just using 50 as an example, i have no idea what it really will be". And you should have amps, ( 12/50=.24 amps.....) Just using as an example!!! TADA! hope it helps.

jw0752 · Answer

Peltiers are notoriously power hungry. If he has a variable power supply he could start at a low voltage and measure the current at successive points inorder to graph the power curve of the peltier. If his ammeter or power supply can't handle the full draw at the 12 volts he can interpolate the graph in order to estimate the current at the 12 volts. As Don pointed out don't expect the graph to be a straight line. John

finding out the amp usage of a part

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