Idiomas disponibles
Idiomas disponibles
4 Measurement Tutorials
AC voltage measurements
The main purpose of an AC "front end" is to change an AC voltage input into a DC voltage which can be measured by
the ADC.
Signal conditioning for AC measurements
Input signal conditioning for AC voltage measurements includes both attenuation and amplification. An input
coupling capacitor (C) blocks the DC portion of the input signal so that only the AC component is measured.
Ranging is accomplished by combining signal attenuation from the first-stage amplifier and gain from the second-
stage amplifier.
The first stage implements a high input impedance (1 MΩ) switchable compensated attenuator. The second stage
provides variable-gain signal amplification to scale the input to the AC converter to the fullscale level. Any residual
DC offset from the attenuator and amplifier stages is blocked by a capacitor.
An AC voltage front end similar to the one discussed above is also used to measure AC current. Shunt resistors
convert the AC current into an AC voltage which can then be measured. Current shunts are switched to provide
selectable AC current ranges.
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Keysight DAQ970A/DAQ973A User's Guide
