E.technical Information; Measurement Principle - Keysight E4981A User Manual

Keysight E4981A 120 Hz/1 kHz/1 MHz Capacitance Meter
User Manual
E Technical Information
This chapter provides technical information on the operating principles of the
E4981A and the basic principles of capacitance measurement.

Measurement Principle

This section explains the underlying principle of how the E4981A is used to
measure the impedance of a DUT.
Figure E-1 Circuit model of impedance measurement
Figure E-1
E4981A. Vs is the measurement power supply voltage, and Rs is the output
resistance of the E4981A. When voltage applied to a DUT is V and current
flowing through the DUT is I, impedance Z is expressed by the equation Z = V/I.
Z consists of a real part and an imaginary part.
diagram of impedance.
illustrates the circuit model of impedance measurement using the
Figure E-2 shows the vector