Re: [CAD_CAM_EDM_DRO] Re: Power Supply & Gecko's

On Saturday 13 August 2005 12:48 pm, turbulatordude wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Roy J. Tellason"
> <rtellason@b...> wrote:
> > On Saturday 13 August 2005 11:42 am, Peter Reilley wrote:
> > > I believe that you cannot measure AC ripple with an AC meter where
> > > there is a DC component. The meter does not filter out the DC.
> > > Thus, it get confused. You really need a scope to measure AC ripple.
> >
> > I think this depends on the meter...
>
> Not sure if this is 100% correct,
> from Newport's website
> http://www.newportus.com/manuals/ACGUIDE.htm
>
> True-RMS voltmeters use an integrated circuit which computes the true
> root-mean-square value of complex signals. AC coupling allows the
> measurement of the AC component (or ripple) from a signal with both AC
> and DC components. DC coupling allows the measurement of total RMS, or
> "heating value", including DC and AC components to over 30 kHz.
> (Maximum crest factor (Vp/Vrms) is 3:1). Screw terminals allow the
> selection of AC or DC coupling. True-RMS meters are especially useful
> in monitoring voltage and current supplied to motors or heaters
> controlled by an SCR or triac circuit.

Yep, and "true RMS" meters are few and far between, and much more expensive
than most of what we're likely to be using...

It depends on the meter... :-)