1. When measuring resistance, the component under test on the car must not be charged, and the component under test must not be connected in parallel with other electrical components.

2. Before measuring the resistance of the car, select the range and adjust the multimeter to zero in this range. When the multimeter cannot be adjusted to zero, it means that the battery of the multimeter is low and the battery should be replaced with a new one.

3. When measuring resistance, try to keep the pointer pointing in the middle of the dial to minimize the error.

4. When measuring low-power transistors, do not use the low-resistance ohm setting of the multimeter below R*100 to avoid damage to the transistor due to current overload.

1. When measuring the DC voltage of a car, the knob should be set to V. When measuring the AC voltage, use the other position, and select a range equivalent to the voltage being measured on the car. If the voltage being measured is unknown, the maximum range should be selected for testing.

2. When measuring DC voltage in a car, the positive test lead of the multimeter should be connected to the high potential end of the component being tested, and the negative test lead should be connected to the low potential end. If you cannot determine which end has the higher potential, you can tentatively touch the two test leads of the component being tested. terminal, if the pointer is biased towards the "-" side of the neutral line of DC voltage V, it proves that the test leads are connected reversely.

1. The multimeter and the component under test on the car must be connected in series.

2. When measuring DC current in a car, the multimeter should be placed at the corresponding A, the positive test lead is connected to the high potential end, and the negative test lead is connected to the low potential end, so that the current flows from the positive test lead into the negative test lead and out.

3. When measuring AC current, there is no positive or negative distinction between the test leads. The range should be consistent with the measured current as much as possible. If the measured current value is unknown, the test should be conducted from the maximum range. When the car multimeter is not in use, the gear knob should be placed at the highest AC voltage level.