45
d) Impedance measurement
Make sure that all circuit parts, circuits and compo-
nents and other objects of measurement are dis-
connected from the voltage and discharged.
Proceed as follows to measure impedance:
- Switch on the DMM and select measuring range “
Ω
”.
- Plug the red measuring line into the
Ω
measuring jack (7) and
the black measuring line into the COM measuring jack (8).
- Check the measuring lines for continuity by connecting the two
measuring prods. The impedance value must be approximately
0 - 1.5 Ohm (inherent impedance of the measuring lines).
- Now connect the two measuring prods to the object to be
measured. As long as the object to be measured is not high-
impedance or interrupted, the measured value will be indicated
on the display. Wait until the displayed value has stabilised.
With impedances of >1 MOhm, this may take a few seconds.
- If “OL” (overload) appears on the display, you have exceeded
the measuring range or the measuring circuit is interrupted.
- Always remove the measuring lines from the object to be meas-
ured after completion of the measurement and switch off the
DMM.
If you carry out an impedance measurement, make sure that the measuring points you touch with the measuring
prods are free from dirt, oil, solderable lacquer or similar. Such circumstances can falsify the measured result.
e) Diode test
Make sure that all circuit parts, circuits and com-
ponents and other objects of measurement are
disconnected from the voltage and discharged.
- Switch on the DMM and select the measuring range
.
Press the button
to switch measurement func-
tions. The diode symbol appears in the display. Pressing this
button again takes you to the first measuring function, etc.
- Plug the red measuring line into the
Ω
measuring jack (7)
and the black measuring line into the COM measuring
jack (8).
- When the measurement input/measurement circuit is open
and short-circuited (e.g., if the diode is defective), “- - - - -”
will be displayed.
-
Connect the two measuring prods with the object to be meas-
ured (diode).
- LCD shows “OL” when the Diode is tested in Reverse Direc-
tion, please revise Diode and retest. If LCD still shows “OL”,
the Diode is defective.
- Always remove the measuring lines from the object to be
measured after completion of the measurement and switch
off the DMM.