User manual

Figure 21: Switch the device into the maximum measuring range before each
measurement. In this device, it is 250 V in the direct voltage range.
1 How to Measure a Resistor?
Preparation work:
Bend the connection wires of one resistor of size 330Ω , 330 kΩ and 1 k and 2.2
MΩ. each by 90° so that you can plug them into the experimenting board (see
figure 22).
To have both hands free for measurements, fashion test prods from two about 7 cm
long completely insulated wire pieces by coiling them firmly around the blank
parts of the test prods. About 1 cm should remain straight. Use this aid to plug
the test prods directly onto the experimenting board.
To measure a resistor, you do not need any external power source like a 9 V
battery. A power source for impedance measurements is installed in the
multimeter already.
Now plug the two test prods in parallel to a resistor on the experimenting board
and set the instrument to the impedance range of 2,000 kΩ. Measure all three
resistors in this manner. Two measurements will show you "001" and the third one
"1—".
These measured values are not very helpful,l even though you did everything
right. What is that? It's about choosing the right measuring range. See exercise
2 for more on this.
Figure 22: After bending the connection wires of 3 resistors by 90° each at the
sides, plug them onto the experimenting board.
Figure 23: About 7 cm long blank wire pieces are coiled around the test prods.
Figure 24: The measuring lines can be connected right to the experimenting plate
in this manner.
Figure 25: In the highest measuring range that can be set, the measuring results
are still rather imprecise.
Avoiding Measuring Errors
According to the last exercise, two resistors were of the same size. You are
noticing a measuring error because the measuring range is set incorrectly.
Therefore, measure every resistor again at the circuit and reduce the measuring
range step by step.
"1" for 1 kΩ in the 2,000 kΩ range turns 0.98, i.e. 980 Ω, in the 20 kΩ
measuring range.
Now switch to the 2,000-Ω-range, determine a measured value of 983 Ω. You have
now determined the best and most accurate measuring range. If you switch down to
the 200 Ω area, you will only see "1—" in the display. This means that the
measuring range set is too small.