RMS vs Average voltage

[amgen]

because of the phase shift between voltage and current- for inductive and capacitive loads, but for pure resistive loads, the current and voltage are in sync

[richard]

it has nothing to do with phase shift or inductive and capacitive loads its simple mathematics

power is whats being measured here
power = V squared / R
the effective power is the sum of the instantaneous powers measured in your wave form, try it for a triangular wave
R=1 ohm Vp=50 , Vave=25v Vrms=28.8

[Charlie]

For starters, the average of a sine wave for a full cycle is 0.

[richard]

For starters, the average of a sine wave for a full cycle is 0.

yes Charlie the average voltage = 0 and the average current =0 yet the load resistor gets hot . perhaps you have just discovered dark energy

[Charlie]

yes Charlie the average voltage = 0 and the average current =0 yet the load resistor gets hot . perhaps you have just discovered dark energy

Well, Richard, you did bring up the math. And the mathematical reason we don't use average is that it's no where near correct, in fact the average IS 0. This is a sine function, so calculating the absolute value average is a bit more complicated. You need to integrate the area under the curve as was outlined above. The way you do that is to square all the instantaneous values, take the average, then take the square root of that. For a sine function, that is the peak to peak value * square root of 2 (0.707)