Specific steps for electronic circuit debugging(II)

(1) Power-on observation: Do not rush to measure electrical indicators after power-on, but observe whether there is any abnormality in the circuit, such as whether there is smoke or not, whether there is abnormal smell, hand-integrated IC package, whether it is hot or not. If an abnormality occurs, turn off the power immediately, and then power on again after troubleshooting.

(2) Static debugging: Static debugging generally refers to the DC test performed under the condition that no input signal is added, or only a fixed level signal is applied. The potential of each point in the circuit can be measured by a multimeter, and the theoretical estimation value is obtained. Comparison, combined with the analysis of the circuit principle, to determine whether the DC working state of the circuit is normal, and timely discover the components in the circuit that are damaged or in a critical working state. By changing the device or adjusting the circuit parameters, the DC operating state of the circuit meets the design requirements.

(3) Dynamic debugging: Dynamic debugging is performed on the basis of static debugging. Add appropriate signals at the input end of the circuit, and sequentially detect the output signals of each test point according to the flow direction of the signal. If abnormal phenomena are found, it should be analyzed. The reason, and troubleshooting, and then debug until the requirements are met.

You should not rely on the instrument for observation or impression alone. When using an oscilloscope, it is best to put the signal input mode of the oscilloscope into the "DC" block. By DC coupling, you can observe the AC and DC components of the measured signal at the same time.

Through debugging, finally check whether the various parameters of the function block and the whole machine (such as signal amplitude, waveform shape, phase relationship, gain, input impedance and output impedance, sensitivity, etc.) meet the design requirements, and if necessary, further on the circuit The parameters propose reasonable corrections.