On Thursday, 11 July 2019 04:54:24 UTC+1, Phil Allison wrote:
** Nutcase Thornton spewed:

tabby wrote:


I wonder if the meter reading has a consistent relationship to the RMS
value. E.g., if the meter always used the peak value, the actual value
would simply be 0.7 the read value. If it was consistent, I could
calculate the correction factor by measuring the peak on a scope. But I
wouldn't want to have to generate correction curves.

When I looked into this decades ago, digital meters typical read the peak & reported 71% of that.

** Nope - non RMS multimeters do just what analogue multimeters do and scale the average value of the rectified AC wave.

I just tried two '80s 3.5 digit DDMs and found they read 125mV on a wave that was 300mV peak. The wave was 50Hz with a few harmonics, the current draw of a small amplifier.



..... Phil

Ah yes, the sample of 2 proves how the rest of the universe is.