ODS Filtering Question

[cdemike]

I'm glad I re-searched this because I was about to ask how to scale filtering from 50w to 100w or vice-versa in the tech section. Really helpful mathematical analysis -- thanks!

I did want to get clarification on something, though: it's not really clear to me why filtering would scale as a square-root basis rather than linearly. Maybe it'd be helpful if I laid out how I was thinking about it. The formula I'm familiar with and use for power calculations is P=IV (and variations thereof mostly using substitutions derived from Ohm's law), and the formula I dug out of the old physics textbook for energy stored in a capacitor is E=0.5C(V^2). Assuming no differences in ESR or the B+ dropping string and taking into account that power is energy over time, I can't see a reason why energy stored in a capacitor wouldn't be a reasonable stand-in to determine a filter capacitor's role in a circuit since the time involved should be the same. Since someone trying to scale 50w to 100w or vice-versa would likely keep B+ the same or reasonably similar, it could be considered constant. So with the assumption of equal B+, the power function could be reduced to P=I, where the only difference would be the current requirements of the output section (should scale linearly as multiples of push-pull pairs in this case). Turning to the energy stored in a capacitor, voltage is again constant, as is the coefficient 0.5, so we'd get E=C, which again should scale linearly.

Where am I going wrong?

[martin manning]

I don't have a complete theory, but I don't think it's just steady-state power. At this point it's a correlation, where the square root relationship seems to fit quite well with observations.