DC AC TRUE RMS
DC
of the waveform, and is given by the expression :
AC True RMS is a term which identifies a DMM that responds accurately to the total effective RMS value regardless
DC +
DC + AC True RMS voltage measurement, you can accurately measure the voltage values regardless of the waveforms
such as: square, sawtooth, triangle, pulse trains, spikes, as well as distorted waveforms with the presence of harmonics
and DC components / Harmonics and DC components may cause:
AC True RMS voltage is the total effective voltage having the same heating value corresponding a DC voltage. With
1) Overheated transformers, generators and motors to burn out faster than their rated life
2) Circuit breakers to trip prematurely
3) Fuses to blow
4) Neutrals to overheat due to triplen harmonics present on the neutral (180Hz)
5) Bus bars and electrical panels to vibrate
Only AC or True RMS and Average responding meters can introduce significant errors in many applications.
See TABLE 2 for typical example.
WHAT IS DC + AC TRUE RMS
®
INPUT WAVEFORM
DC + AC TRMS
AC RMS
AVERAGE RESPONSE
Sine
1.414V
0V
1.414V
0V
Half wave rectified Sine
Full wave rectified Sine
1.414V
0V
1.414V
0V
50% duty pulse train
1.000V
ERROR=
0%
CF=1.414
1.000V
ERROR=
0%
CF=1.414
1.000V
ERROR=
0%
1.000V
ERROR=
0%
CF=1.414
0.436V
ERROR=
56.4%
CF=3.247
0.421V
ERROR=
57.9%
0.707V
ERROR=
0%
CF=2.000
0.546V
ERROR=
22.7%
CF=2.591
0.550V
ERROR=
22.2%
1.000V
ERROR=
0%
CF=1.414
0.707V
ERROR=
29.3%
CF=2.000
0.785V
ERROR=
21.5%
TABLE 2. WAVEFORMS AND CREST FACTORS
