1. ## sinusoidal power help

An ac sinusoidal voltage has a peak to peak value of 30v. What is the RMS value and average value?

If anyone can show me how to do this, ie, the right formulas to use, that would be great. Thanks.

2. Originally Posted by bobchiba
An ac sinusoidal voltage has a peak to peak value of 30v. What is the RMS value and average value?

If anyone can show me how to do this, ie, the right formulas to use, that would be great. Thanks.
As the voltage is positive as often as it is negative the average voltage is 0.

The mean square of a sinusoid of amplitude A is A^2/2, so the RMS is A/sqrt(2)
In this case A=15V, so the RMS is 15/sqrt(2) ~= 10.6 V.

RonL

3. where did a=15v come from?

4. Originally Posted by bobchiba
where did a=15v come from?
Peak to peak is 30 V, so the amplitude of the wave must be half of that, ie. 15 V.

-Dan