Look at Figure A. The figure shows two waveform graphs. Figure A shows a graph of an AC waveform, and Figure B shows a graph of a DC waveform. As you would expect, the DC voltage remains at its peak value all the time (115 volts in this case). The AC voltage, on the other hand, varies constantly. If we’re measuring an AC voltage with a multimeter, at what point on the graph will our measured voltage occur?

Well, it can be shown mathematically that the effective value of AC voltage is actually about 70 percent of its peak value. Thus, if an AC voltage with an effective value of 115 volts was applied to a heating element, the element would produce the same amount of heat as it would with a 115-volt DC voltage applied. The effective value of an AC voltage is also called the RMS or root mean square value. This term refers to the mathematical process that’s used to calculate the effective value.

	Created by That Yeti Dog Person over 3 years ago

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