Greenlee CMT-90 Manual De Instrucciones página 7

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 Greenlee CMT-90 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
Rectified Value
Crest Factor*
(ξ)
* The crest factor is the ratio of the peak value to the RMS value; it is
represented by the Greek letter ξ.
100 100
90 100
1.414 1
100 100
87 64
1.73
CMT-90
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