(1) Not online detection:

(2)Online detection:

b. The internal voltage of the multimeter's electrical barrier must not be greater than 6 V. It is best to use the R×100 or R×1 K range for the measurement range.

a. The multimeter must have a large enough internal resistance, at least 10 times greater than the resistance of the circuit being measured, to avoid causing large measurement errors.

c. Anti-slip measures should be taken for the test leads or probes. Any instantaneous short circuit can easily damage the IC. The following method can be used to prevent the test lead from sliding: take a piece of bicycle valve core and put it on the test lead tip, and extend the test lead tip by about 0.5 mm. This can not only make the test lead tip well in contact with the tested point, but also effectively prevent slipping, even if There will be no short circuit even if it hits adjacent points.

③ AC working voltage measurement method: In order to grasp the changes in the AC signal of the IC, a multimeter with a dB jack can be used to approximately measure the AC working voltage of the IC. When testing, put the multimeter in the AC voltage setting, and insert the positive test lead into the dB jack; for multimeters without dB jacks, a {{0}}.1 to 0.5 μF DC blocking capacitor needs to be connected in series to the positive test lead. This method is suitable for ICs with relatively low operating frequencies, such as TV video amplification stages, field scanning circuits, etc. Since these circuits have different natural frequencies and different waveforms, the measured data are approximate and can only be used for reference.