Re: capacitor calculation for ripple for smps i/p and o/p
This suggests a high voltage supply. Supposing it is 450 V... then 750W calculates to 1.67 A.
Effective load 270 ohms.
1/100 is the idle gap time (time between current bursts of rectified 50 Hz mains AC).
A 940 uF cap, and 270 ohms, makes a time constant of .25 sec. Charge level would fall 63% in that time.
Therefore in .01 seconds it falls 2.5%. ( 63 * .01 / .25 ) (Although the discharge curve is not straight, we assume it is, to make things easy.)
2.5% of 450 makes 11.3 V of ripple.
This can only be a rough estimate. It's not a surprise that it's lower than your colleague's figure.
Consulting another source, here is a simulation:
It agrees better with your colleague's figure.
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