Promax PD-183 Manual Del Usuario página 42

The relationship between the total true RMS (AC+DC) and the
component AC and DC signals is given by the following expression:
True RMS =
RMS is equivalent to that DC value which dissipates the same
amount of power in a resistor.
" Average-responding " meters provide accurate RMS readings for
sinusoidal signals, but can introduce significant errors when
measuring nonsinusoidal waveforms.
The following table shows the errors that result when the average-
responding measurement is used instead of the True RMS value.
Power Calculations (watts) from Voltage Measurements
AC RMS average
responding
Sine wave
Square wave
Triangle wave
This multimeter is AC coupled and will accurately measure the AC
RMS component of an input signal. The DC voltage function will
measure the DC component. To obtain the total true RMS value,
measure the RMS AC component on the AC function and the DC
component on the DC function. Then, calculate the True RMS value,
using the measured AC and DC components and the True RMS
expression given above.
Page 12
√
(AC RMS Component)
VRMS
=
Power
R
(VpK=100V, Load=1kW resistor)
AC True RMS
USER'S MANUAL PD-183
2
+ (DC Component)
2
2 VDC
=
R
5.0
12.3
3.1
2
Error
0%
+23%
-6%
07/2015