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Ripple factor

by wellorderingp
Tags: factor, ripple
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Aug22-14, 11:08 PM
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Quote Quote by Okefenokee View Post
I blundered it. I fixed it quickly but not before you noticed it.

Oh,okay. Thanks by the way now I am atleast clear with what rms is.

Now if I want my bulb to glow brighter I should not use pure ac nor pure dc but a combination of both(equally).
jim hardy
Aug23-14, 05:17 AM
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Quote Quote by wellorderingp View Post
Thank you.
Now if we go by the exact mathematical definition of rms-
Rms value of a function f(t) with period T
Some formula in which we integrate the function with limits 0 to T and take the avg over T
In case of the sine wave of the output half wave rectifier -
We integrate with limits 0 to T/2 and take the avg over T or T/2? because if I use T/2 I get the wrong result.
good - your calculus is probably fresher than mine (1964).

Take average over T not T/2. One whole line cycle. If you use T/2 you haven't accounted for the second half cycle where the function has value zero and your mean will be too high.

And i think you implied integrating the function^2 ?

Well done ! Thanks ! We all love to see "the light go on" .


I woke up worried i might've been ambiguous, or wrong...

We only integrate to T/2 because after that the function is no longer a sinewave.
Maybe you're sharp enough to write the equation of a halfwave rectified sine but i'm not.

So we integrate to T/2 accumulating the mean of sin^2 curve for that first half cycle
and realize that mean is spread over twice the period of integration making it half as big
so there's a 1/2 underneath the radical
which puts a √2 into our result
that's why:
RMS output of a full wave rectified sinewave is Vpeak/√2
but a half wave is Vpeak/2
less by only √2 not half. Root comes after Mean.

So T1 to T/2 are limits of integration
but T1-T2 is the interval over which we average.

You said it exactly right.

Bravo ! And Thanks Again for closing the loop .

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