RE: HV Meter

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mccauley, Daniel H by way of Terry Fritz <twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>


The meter is labelled as being electrostatic:
1) Am I correct in assuming that this means that it's DC only?
2) If (1), would an MO diode and capacitor make adequate rectification for
it?

Yes, any typical rectifier configuration should work as long as your
components are rated as such.

3) Would I be reading peak or RMS with such a half-wave arrangement?

Neither.  I believe half-rectified with large filter capacitor will read :

Vout = Vpeak / 3.14

For full wave rectification with large filter capacitor will read :

Vout = (Vpeak * 2) / 3.14

As you can see, it can be very difficult to implement an analog circuit
capable of getting
true RMS measurements.

Basically you need to take the absolute value of the signal, square that
signal, and simulatenously integrate
that signal over one period.

Of course, you could always use just a single diode and capacitor and make a
peak detector.  The output voltage
of this type of circuit would be the peak voltage - forward diode voltage
drop (plus any ripple on there)

Dan