basildogann said:
measure ac ripple on dc p/s o/p using a DVM.
How accurate is this method compared to scope?
thanks.
Scope method unless it's a modern one ( LeCroy) or so can work it out on a side bar or like Lissajous patterns has to workd geometrically. I'm old fashioned and still use Lissajous for certain measurements.
As AndrewT mentions...weird current measuremts can be haphazard......One pays the price for a true rms meter with good b/width which incidentally is the norm measurement.
Futuristically, If one is advancing into PFC development or anything to do with efficiency measurements, one soon realises a good dvm with true rms readings coupled with good b/w is a sound investment.
For some time I felt a duffer when I realised that my output readings where nearly better than my input ones......beware of Normal DVMS non rms !!
richj