Electrical – Digital multimeter – How does the wrong probe insert (input) alarm work

multimeter

I'm using a digital multimeter (UT61E) and it doesn't have the "Wrong Probe Insert" alarm feature.

I mean when I select the Voltage Measurement with the knob but leave the probes in the Current Terminal, it will sound an alarm and vice versa.

I made this mistake all the time, so I want to build a circuit to do this and mod it on my multimeter.

I've been googling for a while but can't find out how this circuit is made. Maybe a simple idea or some explanation of the principle would help me a lot.

I really don't understand how the meter knows if the probe is inserted or not?

Best Answer

The meter's microprocessor knows what position the knob is in. It can also know what terminal the probe is in by a switch at the bottom of the hole.