AC Voltage

Please note this blog was originally published on the 12th October 2012. It was updated on the 27th May 2021 to include links to relevant Multimeter brands and company contact details.  When you use a multimeter to measure an AC voltage or current, the reading on the meter is an "RMS" or "root mean square" reading. We sometimes call the RMS value the "effective value" of an AC voltage or current. By that, we mean that the RMS value of an AC voltage or current has the same effect as a DC voltage or current of the same value. Continue reading →