JohnGaltLine posted:Rtr and Junior, That .637 ought to be .707 first off.
I disagree. The 0.637 is indeed 0.637, or more precisely 2/pi. Pi being the mathematical pi 3.1415...
The math is somewhat nerdy but is exactly calculated by using integrals as shown above. What you are calculating in closed-form (in that there is an exact mathematical solution), is the average value of a half-cycle of a sine wave. So this is done by integrating the sine function for a half-cycle (or 0 to pi), then taking the average by dividing by pi. Pretty geeky but that's what it is.
If junior is/was measuring the DC voltage at the output of the bridge rectifier he will indeed measure about 0.637 x the peak voltage. But I'm pointing out this is not the relevant DC voltage to measure since the switch machine and LEDs see only half of that average voltage in the method it is hooked up (using only 1 diode of the 4 available diodes).
