How Do Digital Multimeters Measure Voltage, Current, and Resistance?

[Vectronix]

How exactly do digital multimeters measure things like potential difference, electric current, and electrical resistance?

 

[mgb_phys]

They really only sense voltage. They measure current by putting the current through a small resistor and measuring the voltage across it.

They measure the voltage with an analog-digital-converter (ADC), there are a few different types but basically they are a source of different fixed voltages and a an amplifier to compare each fixed voltage with the measured voltage until they are are equal - then use that number.