Protek Z9216 - Page 15

Table 2-5 Extreme Range Error Terms for Capacitances (C + D mode), K
h
and K
l
Frequency K
l
K
h
100 Hz, 120 Hz (2 pF/C
m
) (C
m
/1600 mF)
1 kHz (0.1 pF/C
m
) (C
m
/160 mF)
10 kHz (0.01 pF/C
m
) (C
m
/16 mF)
100 kHz (0.02 pF/C
m
)
(C
m
/200 µF)
Note: C
m = Measured Capacitance Value
Table 2-6 - Extreme Range Error Terms for Capacitances (C + R mode), K
h
and K
l
Frequency K
l
K
h
100 Hz, 120 Hz (2 pF/C
m
) (C
m
/2000 mF)
1 kHz (0.1 pF/C
m
) (C
m
/200 mF)
10 kHz (0.01 pF/C
m
) (C
m
/10 mF)
100 kHz (0.01 pF/C
m
)
(C
m
/100 µF)
C+R Accuracy
The basic impedance accuracy depicted in Figure 2-1 applies to capacitance measurements when
the impedance is interpreted to be 1/2π f C, where f is the test frequency in Hz and C is the
capacitance in Farads. For convenience, Figure 2-1 is redrawn in Figure 2-3 with lines of constant
capacitance superimposed. Also, Table 2-3 is recreated for capacitive impedances in the C + R
measurement mode as Table 2-6. Note from Table 2-6 that the range error factor K
l
is negligible for
capacitances below 1590/f µF
For small values of D (D < 0.1), the accuracy of the capacitance measurement in the C + R mode
is calculated from equation (4a) above, and the accuracy of the resistance measurement is given by
Accuracy of R in % = ± [A
c
× (1 + 1/D)] (5a)
where A
c
is the accuracy of the capacitance measurement and
D = R/2π f C. (5b)
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