Operation Manual

36 GMC-I Messtechnik GmbH
Measurements: V/Hz – Ω – – Temp – – m – A/Hz
5.6 Capacitance Measurement
Ð
Disconnect supply power from the electrical circuit of the device to
be measured, and discharge all high-voltage capacitors.
Ð Make sure that the device under test is voltage-free.
Capacitors must always be discharged before measurement is
performed.
Interference voltages distort measurement results!
Refer to chapter 5.1.1 regarding testing for the absence of
voltage with the help of the direct voltage measurement.
Ð Set the rotary switch to “ ”.
Ð Connect the (discharged!) device under test to the sockets
with the measurement cables as shown.
Note
The “–” pole of polarized capacitors must be connected to the
“ ⊥ ” jack.
Resistors and semiconductor paths connected in parallel to the
capacitor distort measurement results!
Note
This function is to be used espcecially for the measurement
of components. For telecommunications networks, the spe-
cial capacitance measurement is recommended, see chap-
ter 6.4
5.6.1 Cable Length Measurement m
In the cable length measuring mode, the instrument calculates
length as a function of the capacitance value entered by the user:
Preparation and execution of this measurement is the same as for
capacitance measurement.
Ð Press the yellow multifunction key FUNC | ENTER.
“k” and “m” (i.e. kilometers) appear at the display instead
of “F”.
Refer to chapter 7.4 with regard to adjusting the “CAP” scaling
factor (capacitive linear electric constant).
Note
When measuring cable length, make sure that the cable
parameters (e.g. cross-section) are identical. Varying cable
parameters, for example interconnected cables of varying
type or cross-section, distort measurement results.
Note
This function is to be used espcecially for the measurement
of components. For telecommunications networks, the spe-
cial cable length measurement is recommended, see chap-
ter 6.4.1
Length (km) =
measured capacitance (nF)
capacitance value (nF / km)