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f)Frequency Measuring
The DMM can be used to measure and indicate signal voltage frequencies from 10 Hz to 10 MHz.
Proceed as follows to measure frequencies:
- Switch on the DMM and select measuring range “Hz”. The display reads
“Hz”.
- Plug the red measuring line into the Hz measuring jack (7) and the black
measuring line into the COM measuring jack (8) .
- Now connect the two measuring prods to the object to be measured (signal
generator, switch etc.).
- The frequency and corresponding unit are displayed.
- After measuring, remove the measuring lines from the measured object
and turn the DMM off.
g) Resistance Measuring
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Make sure that all the circuit parts, switches and components and other objects of
measurement are disconnected from the voltage and discharged.
Proceed as follows to measure the resistance:
- 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 both measuring
prods with one another. The resistance value must be approximately
0 - 0.5 Ohm (inherent resistance of the measuring lines).
- For low-impedance measurements, press the button “REL” (3) to not let the
inherent resistance of the measuring lines flow into the following resistance
measuring. The display shows 0 Ohm. The automatic range selection (auto
range) is inactive. The autorange function is activated again by switching
the measuring function (e.g. press button “SELECT” 3 x).
- Now connect the 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 resistances 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 has been broken.
- After measuring, remove the measuring lines from the measured object and turn the DMM off.
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If you carry out a resistance measurement, make sure that the measuring points which you
contact with the test prods are free from dirt, oil, solderable lacquer or the like. Such circum-
stances can falsify the measured result.
