Selecting Circuit Mode Of Capacitance - Keysight E4980A User Manual

Measurement Procedure and Examples
Parallel/Series Circuit Mode

Selecting Circuit Mode of Capacitance

The following description gives some practical guidelines for selecting the
capacitance measurement circuit mode.
Small Capacitance (modeled by (a) in
Small capacitance yields large reactance, which implies that the effect of the parallel
resistance (Rp) has relatively more significance than that of series resistance (Rs). The
low value of resistance represented by Rs has negligible significance compared with
the capacitive reactance, so the parallel circuit mode (Cp-D or Cp-G) should be used.
Large Capacitance (modeled by (b) in
When the converse is true and the measurement involves a large value of capacitance
(low impedance), Rs has relatively more significance than Rp, so the series circuit
mode (Cs-D or Cs-Q) should be used.
Figure 7-4 Capacitance circuit mode selection
The following rule of thumb can be used for selecting the circuit mode
according to the impedance of the capacitor.
Above approx. 10 k
Below approx. 10 
Between above values
For example, to measure a 20 F capacitor at 1 kHz (impedance will be
approx.8 ), the Cs-D or Cs-Q function is suitable.
Keysight E4980A/AL Precision LCR Meter
Figure 7-4)
Figure 7-4)
Use parallel circuit mode
Use series circuit mode
Follow the manufacturer's recommendation
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