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circle as a potentiometer, which makes it possible to smoothly change
the voltage between the points D and E from zero to maximum
voltage.
Before switching on the unit, set the potentiometer to “zero”

voltage.
When the current source is off, measure the diameter of the
conductor d and set the moving contact C to the upper position and

determine the length of the conductor on a scale ruler. l  AC. Data are
put into the table 37.1.
2. Turn on the device and potentiometer by increasing the
voltage, to research the dependence of the current strength І on the
2
voltage U. You need to get at least 5 experimental points. Data is put
into the table 37.1.
3. Similar studies should be carried out for other conductor

sections (other lengths of the AC), for example, by successively
reducing them by 5 cm. Data are put into the table.

Table 37.1.

Length of conductor AС

l =500 mm l =450 mm l =400 mm l =350 mm l =300 mm
4
1
2
3
5

І, І, І, І, І,
U, V U, V U, V U, V U, V
mA mA mA mA mA
1.
2.
3.
4.
5.

4. Processing of the experimental data.
1. Process the experimental dependences of the current strength
in the conductor on the voltage at its ends at different values of

resistance of the conductors (of different lengths of conductors).
Analyze the obtained dependencies (whether the linear dependence of

2
In this installation, high-level high-sensitivity volt-meter is used, so
when calculating, the current through a voltmeter might be neglected.

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