Solution
No, the NI 4072 and the NI 4082 are not able to measure impedance. However, impedance can be calculated by measuring resistance, capacitance, and inductance independently, as the NI 4072 and NI 4082 were designed. For more information about the theory, see
Capacitance/Inductance Measurements with PXI DMMs.
To ensure measurement accuracy, the load that is measured should be as close to purely inductive, capacitive, or resistive as possible.
Resistance MeasurementsThe NI 4072 and the NI 4082 makes resistance measurements using a constant-current technique. A current is supplied to the resistance under test, and the DMM measures the resulting voltage as represented in the following figure.
Figure 1: Circuit Configuration of DMM Measuring a Resistor
Capacitance/Inductance Measurements
The NI 4072 and the NI 4082 uses a multi-tone AC current source as the excitation signal necessary to measure capacitance and inductance. The current waveform is a very stable, harmonically limited square wave which is applied to the device.
Figure 2: Circuit Configuration of DMM Measuring a Capacitance or Inductance
Note: Bold values denote vector quantities or complex numbers.