Giles, This is what I figured, but what would be the "peak" value? In an AC sinewave the peak value is half of the peak to peak value and the RMS is the peak x 0.707. Is their a math formula for finding the peak value? Thanks for your help! Steve -----Original Message----- From: Giles Honeycutt [mailto:giles-pl@AMTECH-ENG.COM] Sent: Monday, September 16, 2002 9:06 AM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Measuring the peak value of an AC squarewave. Steve, The formula for the RMS of a AC square wave is Divide by 2 Or you can just flip the negative, and you have DC and DC is RMS Best regards, Giles ----- Original Message ----- Subject: [EE]: Measuring the peak value of an AC squarewave. Friends, I am having a problem that I really need help with. I am trying to measure an AC squarewave at 800Hz with a dutycycle of 50%. I am using a Keithley 2000 multimeter set to read ACV. I need to measure the volts peak, the meter gives me the volts RMS. I figure I could do the formula but nothing matches. I am measuring 5.6Vpp and 2.8Vrms. This doesn't make any sense to me. When I measure the sinewave of an equivelant circuit everything works out mathematically. Could someone point me to a possible solution. I have a feeling I am missing / forgetting something trivial. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.