Hioki DT4282 - Appx. 3 Capacitor Capacity Measurement; Principle

Appx.3
Capacitor Capacity Measurement Principle
Appx. 3 Capacitor Capacity
Measurement Principle
The instrument measures the capacity using the CR self-excited
oscillation method (triangle wave).
R: Instrument internal circuit Varies with each range.
C: Object to be measured Capacitor
When the capacitor to be measured is connected, self-excited
oscillation begins. The capacity is calculated based on the
measured frequency during self-excited oscillation. The frequencies
during self-excited oscillation are shown in the table below.
Measurement
range
Resistance of the
instrument internal circuit
Reference oscillation
frequency
1 nF 100 k
Ω
500 Hz to 600 Hz
10 nF 100 k
Ω
300 Hz to 600 Hz
100 nF 100 k
Ω
60 Hz to 600 Hz
1 µF 100 k
Ω
6 Hz to 600 Hz
10 µF 5 k
Ω
15 Hz to 5100 Hz
100 µF 5 k
Ω
1.5 Hz to 5100 Hz
1 mF 5 k
Ω
5 Hz to 9300 Hz
10 mF 5 k
Ω
0.5 Hz to 9300 Hz
100 mF 5 k
Ω
0.05 Hz to 9300 Hz
Even when the same capacitor is measured, the capacity may vary
depending on the measurement range. This is because the oscillation
frequency is different even in the same capacitor since the resistance R
of the instrument internal circuit changes for each measurement range.
Consequently, the capacity differs as shown in the table below depending
on the measurement range when a measurement target that is frequency-
dependent, such as an electrolytic capacitor, is measured. The table shows
the capacity for each frequency and contains true values.
Ind.Appx.
7
6
5
4
3
2
1
HIOKI DT4281A981-08