While using a digital multimeter to diagnose electrical problems on customers’ equipment, I frequently hear the comment, “I’ve got one of those multimeter things, but I never learned how to use it.” ...

Measuring a floating dc voltage using a microcontroller’s analog-to-digital converter (ADC), with the dc+ to dc– ranging from 2.5 to 30 V and the low side able to float as high as 120 V above logic ...