Assuming f(t) is a voltage applied across a 1ohm resistor then the average power in the signal f(t) is:-

The applet below shows how the power in the harmonics approaches the wave power as the number of terms summed is increased. Psq is the power in the harmonics for a square wave and Ptr is for a triangular wave. In each case, the power is normalised to the wave value.

When activated the following gif image show how the applet should appear.

COPYRIGHT © 1996 Cuthbert Nyack.