User`s guide

Measurement Tutorial 3
U2741A User’s Guide 55
AC Measurements
True RMS AC measurements
True RMS responding digital multimeter, like the U2741A,
measure the "heating" potential of an applied voltage. Power
dissipated in a resistor is proportional to the square of the
voltage waveform. This digital multimeter accurately
measures true RMS voltage or current, as long as the wave
shape contains negligible energy above the instrument's
effective bandwidth.
NOTE
The U2741A uses the same techniques to measure true RMS voltage and
true RMS current.
Ta bl e 3 - 3 Waveform shapes and their parameters
Waveform shape Crest factor (CF) AC RMS AC+DC RMS
2
V
2
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V
2
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3
V
3
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V
3
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User's Guide.book Page 55 Friday, August 8, 2008 9:11 AM