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8 Judgment Methods for Circuit Fault Detection

Views: 210     Author: Site Editor     Publish Time: 2020-10-22      Origin: Site

The troubleshooting of electronic circuits can generally be detected by the sequence of input to output, or the reverse method from output to input. No matter which direction you start, electronic short circuit fault detection can generally be judged by the following eight methods.



1. Direct Observation

When a circuit breaks down, under normal circumstances, we will not immediately use the instrument to measure, but only look to find possible abnormal parts of the circuit by eyes. And the direct observation method is divided into no-power and power-on detection.


No-power detection means to check whether the level and polarity of the power supply voltage meet the circuit requirements, whether the polarity of the electrolytic capacitors, the pin positions of the diodes and transistors, and the pin positions of the integrated circuits have problems such as false soldering, wrong soldering, and crossing. Whether there is an unreasonable place in the wiring, whether the circuit breaks when the printed board is printed, whether the resistance and the capacitor are obviously burnt.


The power-on inspection is mainly to observe whether the components are overheated, smoke and have an obvious burning smell, and whether the filaments of the electron tube and the oscilloscope tube have high-voltage ignition problems.

power short circuit fault

2. Multimeter Testing

The multimeter testing is mainly to check the static operating point, in which the resistance value and DC working status of the power supply system of the electronic circuit, the transistor, the integrated block and the circuit can be tested by the multimeter. Check to see if the value is normal.



3. Signal Tracking Method

In a complex circuit, you can put a signal to the input end, and then use an oscilloscope to observe the waveform and amplitude changes from the front stage to the back stage or from the back stage to the front stage, and finally check which level is abnormal.



4. Comparison Method

The comparison method is more intuitive, mainly by comparing the parameters of the suspected electrical short circuit with the same circuit in normal working condition, finding out whether there is a value with a large parameter difference, and then analyzing the cause of the power short circuit fault, and finally judging the cable short circuit fault location.



5. Replacement Method

For electronic circuits with unobvious failures, when the failure point cannot be visually determined, the same existing components can be used for replacement, and the time for failure determination can be shortened by observing whether the circuit changes through replacement.



6. Bypass Inspection Method

If there is a parasitic oscillation in the circuit, you can use a capacitor of a certain capacity to connect the capacitor across the place to be checked or between the reference ground points, and then observe whether the oscillation exists. If the oscillation disappears, it means that the oscillation is generated in the previous circuit or a nearby circuit. If not, move back and continue to look for checkpoints. Pay attention that the bypass capacitance should not to be too large, so the capacitor can better eliminate the unfavorable signal.

earthing and short circuiting devices

7. Short Circuit Inspection Method

In the short circuit inspection method, we need to take the initiative to create a temporary short circuit, so as to cause some circuits to short circuit. It should be noted that the short circuit inspection method cannot be used on the power circuit.



8. Open Circuit Inspection Method

The short-circuit method mentioned above is the most effective for checking the open circuit. Similarly, the open circuit method for the short circuit inspection is also the most effective. The open circuit inspection method is similar to the previous methods, which is used to eliminate doubts and shorten the scope. Assuming that the regulated power supply is connected to a power line short circuit, and the output circuit is too large at this time, then we disconnect a certain part of the circuit in turn, and then observe the current output of the circuit to determine the branch where the electric wire short circuit fault occurs.


The above eight methods are just some of the most commonly used methods. There are many ways to judge the short circuit in power system, and they can be flexibly applied through different instruments and equipment, so that it will be easier to judge complex short circuit and earth faults.


When choosing the right circuit fault detection methods, we need to use professional earthing and short circuiting devices for testing. Our company mainly produces cable fault indicators to help you detect faults accurately.

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