P to P measurements with an RMS meter?

[Axtman]

How can I measure peak to peak voltage with an RMS multimeter? 

[w2aew]

The answer is - you really can't.  IF the signal you are measuring is a sinewave that is within the frequency range of your RMS voltmeter, then you can calculate the peak to peak value by multiplying the RMS voltage by 2.828. 

[ConKbot]

If its a sine wave youre measuring, mulitply by 2*sqrt(2), or 2.8284.  For RMS to Vpeak its RMS*sqrt(2) but since you want peak-peak, its 2x that.

If its not a sine wave, then make a voltage doubler,

(the transformer in the image is the AC source, substitute with whatever you want to measure) and add ~0.6 to 1V for the voltage dropped over the diodes. The drop would nominally be 1.4V for the 2 diodes, but with no load being drawn, then the Vf of the diodes will drop a lot.

[Wytnucls]

Some true RMS multimeters have a 'Peak" feature, giving you peak to peak values.
Here is an example: (the 71B meter on the left was defective)

[ttp]

Nice to know, I got 71D.