Precautions for measuring integrated circuits with a multimeter
1. A multimeter should have a sufficiently large internal resistance, at least 10 times greater than the resistance of the circuit being tested, to avoid significant measurement errors.
2. The probe or probe should be equipped with anti slip measures. Any momentary short circuit can easily damage the integrated circuit. The following methods can be taken to prevent the probe from sliding: take a section of the bicycle and insert the valve core onto the tip of the probe, and extend the tip of the probe by about 0.5 millimeters. This can not only ensure good contact between the tip of the probe and the tested point, but also effectively prevent slipping, and even if it touches adjacent points, it will not short-circuit.
3. When the voltage of a certain pin does not match the normal value, it is necessary to analyze whether the voltage of that pin has a significant impact on the normal operation of the integrated circuit and the corresponding changes in the voltage of other pins in order to determine the quality of the integrated circuit.
4. The voltage of integrated circuit pins is affected by the periphery. When there is leakage, short circuit, open circuit, or value change in peripheral components, or when a potentiometer with variable resistance is connected to the peripheral circuit, the position of the potentiometer sliding arm will cause changes in the pin voltage.
5. If the voltage of each pin of the integrated circuit is normal, it is generally considered that the integrated circuit is normal; If the voltage of some pins in the integrated circuit is abnormal, we should start from the point where the deviation from the normal value is maximum and check for any faults in the peripheral components. If there are no faults, the integrated circuit is likely to be damaged.
6. For dynamic receiving devices such as televisions, the voltage at each pin of the integrated circuit varies with and without a signal. If it is found that the voltage of the pins should not change but instead changes significantly, and the voltage that should change with the signal size and the position of the adjustable components does not change, it can be determined that the integrated circuit is damaged.
7. For devices with multiple working modes (such as video recorders), the voltage of each pin of the integrated circuit is also different under different working modes.
