Potentiometer Testing Using Oscilloscope

Image Legend:
1 D+, blue
2 FREQ OFF (-), black
3 FREQ OFF (+), blue
4 Terminal 1, black
5 Oscillogram for correct signal passage
6 Oscillogram for disturbed signal passage

Potentiometer Test Using Oscilloscope:

Measuring instrument: BMW SERVICE TESTER

Test leads: FREQ OFF (+), blue; FREQ OFF (-), black; Terminal 1, black; D+, blue

The test is similar to the wire test using the oscilloscope, in this case, however, the measurement is read oft at the wiper pick-off.

Test Procedure:

Connect universal test lead and leads for frequency measurement to the BMW SERVICE TESTER.

Connect the blue D+ lead to the wiper of the potentiometer to be tested. Connect the black FREQ OFF - lead to the one end, the black terminal 1 and blue FREQ OFF + lead to the other end.

Select *M* for multimeter, "22" for oscilloscope, "13" for frequency output. Apply any frequency and press acknowledgement button twice.

To conduct the test, move the potentiometer through its entire measuring range.

If the potentiometer is faulty, the square-wave signal will be interrupted irregularly.