# Re: FAQ questions...

```In a message dated 96-07-09 08:37:40 EDT, you write:

> Is a watt in AC roughly volts*amps?  I believe that a watt is VA in
>     DC, and if you are dealing with RMS Volts and amps, does that make it
>     true for AC?
>
Hi Chip ,

RMS volts is equal to DC volts .
I know this sounds goofy when simply stated this way .
RMS has to do with the area "under the sine curve"
If one were to rectify the sine wave so all the peaks
were on top --- then stomp 'em flat --- (keeping the "volumes" of
the individual peaks constant)     the remaining height would be
representative of the available value of the DC
One Volt DC = 1.414 volts AC (peak )
When measuring the mains voltage (120 VAC) WITH A V.O.M.
one is actually measuring the DC value -----the heating value
---when considering power ---- watts
--- The actual voltage peak is 1.414 times that value (the value to which
a capacitor will charge)
So the 120 vac measurement if expressed in peak to peak terms
would be 120 * 1.414 * 2 or abt 340  volts---(as seen on the o-scope)
Hence  RMS (DC value) = .707 peak

hope this helps

Sandy

```