Haefely 2830, Руководство пользователя, Страница: 29 / 124

Device Functions
21
I
X
Current trough Device Under Test C
X
I
N
Current trough known Standard
Capacitor C
N
I
RX
Losses of the Device Under Test C
X
C
X
Test Object (ideal capacitance)
C
N
Standard capacitor (with tan

< 10
-5
)
R
X
Measuring shunt for I
X
, C
X
R
N
Measuring shunt for I
N
, C
N
V Low voltage point of the HV supply and
reference point of the measurement
ADC Analogue to Digital Converter
t
1
, t
2
Time stamps of the measured values
6.1.2 DC Resistivity
The DC Resistivity measurement is based on a pico ampere meter built-in the 2831 which
measures the current through the liquid or solid test cell. The HV DC source built-in the 2831
energizes the test cell so that a current can flow through the solid or liquid sample and the pico
ampere meter. The applied voltage and the measured current are converted to digital values for
further calculations in the 2830.
To calculate the resistivity, four parameters has to be known: The Ix through the solid or liquid
sample, the applied voltage Utest, the surface area of the measuring electrode A and the thickness
of the test sample l. In the chapter 9.5 DC Resistivity the calculation is explained in detail.