what is root mean square voltage? and why is there a root mean square voltage and a peak voltage? for instance, 120v ac has an RMS voltage of 120v and has a peak voltage of 170 volts

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what is root mean square voltage? and why is there a root mean square voltage and a peak voltage? for instance, 120v ac has an RMS voltage of 120v and has a peak voltage of 170 volts

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6 Answers

Anonymous 0 Comments

AC power isn’t continuous; it’s a sine wave, which goes back and forth across zero dozens of times per second (60 hz and 50 hz are common, which is 60 and 50 cycles per second). So the voltage goes from 0 to 120, back to 0, to -120 (which for things designed for AC power is equivalent to 120), to 0, to 120, etc. very very fast.

Root mean square is the method to figure the average voltage (you can also do it for average power) of that cycle. For a sine wave with a peak of 170v, the average is 120v.

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