2
π
――
τ
PC510a: AC coupling True RMS
When measurement is taken by true r.m.s., the measurement
value of input signal becomes the scales of the signal power
and therefore provide more effective values than those
obtained by average value detection. This multimeter imploys
this true RMS circuit, which enables measurement of sine
wave and non-sinusoidal waves like square wave and
triangular wave in r.m.s.
Crest Factor
The crest factor (CF) is expressed by a value obtained by
dividing the peak value of the signal by its RMS value. Most
common waveforms such as sine wave and triangular wave
have a relatively low crest factor. The voltages and crest factors
of typical waveforms are shown in the table.
— 10 —
Please note the That measurement should be taken at the crest factor
below 3.
2
π
――
τ
τ
2
π
――
•Vp
Sine Wave
Square Wave
Triangular Wave
Puls
Input Waveform
Peak
Vp
RMS
Vrms
Average
Vavg
CF
Vp/Vrms
Form Factor
Vrms/Vavg
Vp
Vp
Vp
1
1
Vp
Vp
Vp
0
π
2
π
Vp
0
π
2
π
Vp
0
π
2
π
Vp
0
τ
2
π
=0.707Vp =0.637Vp =1.414
=1.111
=0.577Vp
=0.5Vp
=1.732
=1.155
Vp
――
2
2Vp
――
π
2
π
――
2 2
Vp
――
3
Vp
――
2
3
2
――
3
Vp
τ
2
π
――
•Vp
