Half wave rectifier.........................?

Question

in a HW rectifier with a capacitor filter..what is the rms value of the AC ripple voltage??
eg...for a full wave rectifier it is given by Vr/(2*sqrt(3))

and when the questio says 'the ripple content must be less than 1% (say) "..does it mean ripple factor must be less than 1% or the ripple voltage must be 1% of the dc output voltage...

Answer 1

It kinda depends on the value of the load. If there is no current being drawn by a load, the capacitor will charge up to the peak value of the input (√2 times the RMS value) and stay there. But if there is a load across the capacitor, then it will drain charge off of the capacitor so that the voltage across the capacitor decays until the next half-cycle charges it up again.
I've always used the approximation
V(p-p)=I/fC where
V(p-p) is the peak to peak ripple, I is the load current, f is th frequency of the input sine-wave, and C is the value of the capacitor. It's usually within 1 or 2 percent.

HTH

Doug

Answer 2

ripple voltage is function of load.