Peltier element is widely used in different instruments especially in biomedical insruments. I want to check the resistance of it. How can I do that?
Take an LCR instrument with a frequence of about 1000 Hz. Don´t use a direct current multimeter, because you get errors because of heating effects.
Only a short hint of me, I´m no Peltier specialist.
Hanno is quite correct - if you apply DC, you will set up a temperature difference which results in a Seebeck voltage, thus disrupting the measurement.
An AC method with a reference resistor is the simplest method. I have conducted measurements with many different frequencies, but to avoid probing contact resistances, for example, a range of tens to hundreds of Hz should be perfectly acceptable.
As an aside, it is good practice to avoid frequencies that coincide with the fundamental (or harmonics) of the mains AC voltage (50Hz in the UK).
The measurement method will depend on what you are trying to do.
Most Peltier devices are semi-conductors, and so the resistance changes with temperature and to some extend applied voltage. If you are trying to build a device using a Peltier module and you need to understand the power consumption, then you need to operate the device close to the operating conditions, in terms of hot and cold temperatures and heat flow. Then measure the current through the device and divide this into the voltage across it. This will give you the resistance at the operating condition. You can then change the operating condition and measure again.
Best Regards
Paul
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