auto polarity in digital multimeter

[Fatih]

Hi everyone, I have decided to join this forum hoping that I will improve myself in electronics.

Currently, I am trying to understand how a digital multimeter works and searching over the internet, but I could not find how auto polarity in digital multimeter works. What is the mechanism for this function in digital multimeters?

I appreciate any effort.
Fatih

[Paul Price]

Have faith, if you google "How to use voltmeter" or "How to use DVM" or search using "DVM" on Youtube you will find plenty of info and tutorial.

Any multimeter can tell the difference if the input positive probe is more positive or negative then the other ground probe and then whether it is positive or negative, the auto-polarity circuit is just reacting to that and changing the display readout to notify you what polarity it detects.

So how does the auto-polarity get sensed? Usually a very high sensitivity circuit called a comparator or an operational amplifier does the job.

In a comparator the output is switched ON or OFF depending on the relative voltages at the PLUS and MINUS inputs of the comparator. The inputs are quite sensitive and a difference of only a few millivolts between them will cause the output to turn on or off.

google or Youtube the words "comparator" to get more info.

[Fatih]

Thanks for your help. I will do as you suggested.