# Diference between Vrms & ac value of a signal

1. Jan 26, 2008

### sphyics

What is Vrms value. How can i measure it practically with whatever instruments (read voltmeter, oscilloscope). is it some mathematical stuff or we can measure it directly as voltage is measured.

so please tell me the difference between rms value and ac value of a signal, is rms value releated to some heating effect.....

Last edited: Jan 26, 2008
2. Jan 26, 2008

### dlgoff

For a sinusoidal wave, you can measure peak voltage, peak-to-peak voltage, average voltage over a half-cycle, or effective (http://en.wikipedia.org/wiki/Root_mean_square" [Broken]) voltage. RMS voltage of an ac source is usually what you will measure with your hand-held multimeter.

Last edited by a moderator: May 3, 2017
3. Jan 28, 2008

### Ouabache

You could also use your oscilloscope, read the peak voltage and multiply by 0.707 (or more specifically, by $\sqrt {2}/2$). If you take a look at this page it may clarify the meaning for you.

4. Jan 28, 2008

### sphyics

thanks dlgoff, Ouabache for the valuable informations.