When Measurement Parameter Is Cs-Rs - Keysight E4981A User Manual

Specifications and Supplemental Information
Sample Calculation of Measurement Accuracy

When measurement parameter is Cs-Rs

The following is an example of calculating the accuracy of Cp and Rs,
assuming that measured result of Cs is 8.00000 nF and measured result of Rs
is 4.00000 kΩ.
Because the Cs accuracy is
3 -9 3
D=2× ×Freq×Cs×Rp=2× ×10 ×8×10 ×4×10 =0.2}0.1, multiply 0.13% (the
p p
2 2
result obtained for Cs-D) by 1+D . The result is 0.13×(1+0.2 )=0.1352%.
From Table 10-6, the equation to calculate the accuracy of Rs is (90+50×K)/Cx.
Substitute K=2.5 (same as Cs-D) and 8.00000 nF of the measured Cs result
into this equation. The accuracy of G is (90+50×2.5)/8.00000=26.875 Ω.
2
Because D}0.1, multiply the result by 1+D as in the case of Cs. The final result
is 27.95 Ω.
Therefore, the true Cs value exists within
8.00000±(8.00000×0.1352/100)=8.00000±0.01082 nF, that is, 7.98918 nF to
8.01082 nF, and the true Rs value exists within 4.00000±0.02795 kΩ, that is,
3.97205 to 4.02795 kΩ.
204 Keysight E4981A 120 Hz/1 kHz/1 MHz Capacitance Meter