Greenlee CM-1200 Manual De Instrucciones página 8

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AC Measurement
AC measurements are usually displayed as RMS ( root mean squared ) values. Two methods of
AC measurement are average-responding RMS calibrated and true RMS-reading.
The average-responding RMS calibrated method takes the average value of the input signal,
multiplies it by 1.11, and displays the result. This method is accurate if the input signal is a
pure sine wave.
The true RMS-reading method uses internal circuitry to read the true RMS value. This method
is accurate, within the specified crest factor limitations, whether the input signal is a pure sine
wave, a square wave, sawtooth wave, half wave or signal with harmonics. The ability to read
true RMS provides much more measurement versatility. The CM-1200 is a true RMS meter.
The Waveforms and Crest Factors table shows some typical AC signals and their RMS values.
Waveforms and Crest Factors
Waveform
RMS Value
100
90
Average Value
Crest Factor*
1.414
(ξ)
* The crest factor is the ratio of the peak value to the RMS value; it is represented by the
Greek letter ξ.
8
100 100
100 87
1 1.73
100
64
2