C) Resistance Measurement "Ω - VOLTCRAFT ET-100 Bedienungsanleitung

c) Resistance measurement "Ω"
Make sure that all circuit parts, circuits, components and any other test objects are currentless
and discharged.
The measuring device allows measuring resistances in the low-resistance measuring range from 0.01 to 400 Ω. For
accurate results, resistance is measured with a test current of approx. 200 mA.
Proceed as follows to measure resistances:
- Switch on the measuring device and select measuring range "400 Ω".
- Plug the red measuring line into the Ω-measuring socket (10) and the black
measuring line into the COM measuring socket (11).
- Check the measuring lines for continuity by connecting both test prods with
one another. The resistance value must be approximately 0 - 0.5 ohms (inher-
ent resistance of the measuring lines) along with a beep.
- Connect the test prods with the test object. The measured value is displayed
as long as the test object is not a high-resistance object or interrupted. Wait
until the display has stabilised.
- IF "OL" (overload) is displayed, you have exceeded the measuring range or the
measuring circuit is broken.
- After measuring, remove the measuring lines from the test object and switch off
the measuring device.
If no measurement can be carried out or if the continuity check fails (zero display), check the built-
in fuse. Fuse replacement is described in chapter "Cleaning and maintenance".
If you carry out a resistance measurement, make sure that the measuring points where you connect the
test prods are free from dirt, oil, solderable lacquer or the like. Faulty measurements may result under such
circumstances.
For low-voltage measurement, the resistance of the measuring lines is included in the
measuring result. Measuring line resistance is approx. 0.5 Ω. The equivalent circuit
diagram is illustrated on the right. Resistances "R E1" and "R E2" represent the
measuring lines. "R" represents the test object. All three resistances contribute to the
measured value. In order to exclude measuring line resistance from the result,
activate the ZERO function.
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