Common troubleshooting of electronic circuits

To rule out the fault of electronic circuit in a timely manner must be based on accurate detection and judgment of fault processing basis, so the focus of the electronic circuit fault handling work should be accurate positioning fault location and the following fault detection methods are introduced in detail. 

 

1, direct observation, direct observation method is also called observation method or sensory perception judgment method, refers to any other testing equipment, but by human touch, smell, hearing, vision and other senses of the failure judgment analysis of electronic circuit, and then locate fault location, and then the corresponding repair measures, make the electronic component return to normal working condition. 

 

The direct observation method includes pre-power and post-electric observation, which mainly observe whether the elements used in electronic circuits are correct, whether the wiring is wrong, and the connection is reversed. Observation on the observation of the presence of charred odors, the presence of smoke in the circuit, whether the color is browned or blackened, etc. 

 

Direct observation method is easy to operate, simple and feasible, and more accurate judgment, it can be as the basis of dealing with complex electronic circuit fault link, in order to improve the working efficiency of the complex fault. 

 

2. Voltage and current measurement method is used to measure the voltage, current and other parameters of the circuit during the maintenance of electronic equipment. 

 

When the circuit voltage is not too high, it is suitable to measure the relative voltage value of each part of the electronic instrument equipment and compare it with the normal working voltage value to determine the fault condition. When the circuit work is unstable, we can use the current measurement method to determine the fault location of the circuit. This situation is more complicated, which requires us to flexibly use the knowledge to judge the failure situation. The fault location can be combined with voltage measurement and current measurement. For example, the current indicates that the main circuit is the path, the voltage representation is zero, and the reason for the failure may be the short circuit of the electrical appliance in parallel with the voltmeter. Neither voltage nor current indicates that no current passes through two tables, and failure can be the main circuit breaking. 

 

3. Parametric test method requires the use of specialized detection instruments and a strong theoretical knowledge to determine the faults in electronic circuits. For example using a multimeter detection current of a line or a certain element of resistance, etc., when the testing value and design standard parameters of current or element is large, the fault may appear in this location, and then adopt the method of replacement of lines or electronic components to troubleshooting. In addition, check the electronic circuit static working point, can use an oscilloscope to determine, this is because the input impedance of the oscilloscope have high detection process to the original circuit of the impact of small, but through the oscilloscope will observe the location to be measured disturbance voltage or signal, can help technicians to quickly find out the cause of the failure. 

 

4, tracking signal tracking signal is the appropriate frequency signal access might malfunction of electronic circuit, then the oscilloscope access circuit, monitor the change of signal and direction of flow, and according to the monitoring signal in the direction of propagation of the circuit, when the detected signal change is bigger, can judge failure preliminary general location, and then make a careful monitoring. This method is of high efficiency in troubleshooting, so it is a common method to monitor electronic circuits, especially in the process of dynamic debugging. 

 

5. Comparative method is the comparison method. Using the comparative method is the premise of have similar to the fault circuit and working circuit, by detecting the normal performance of the circuit parameters, compared with the performance parameters of the circuit of breakdown, mutatis mutandis, to determine fault location and analysis the reason of the failure, this method is suitable for simple electronic circuit fault. 

 

6. Replacement method is full name component substitution method. In electronic circuit troubleshooting methods, element substitution method for fault location accurate positioning, it is using the normal elements replacement may be down electronic components, components after replacement if the electronic circuit back to normal working condition, then it is replaced components damage and led to the failure happened. This method is suitable for use in situations where the fault has been initially determined. If you have not yet determined the range of the fault, then the amount of work to replace the components will be larger, as if it were spread across the sky, and it would be difficult to use this method if you were looking for a melon. 

 

Compensatory method is a common and relatively accurate method of testing. If appear parasitic oscillation phenomenon in electronic circuit, can position the oscillation by selecting the appropriate capacity of capacitor, namely the right position in the electronic circuit of capacitor and ground short circuit, if found in electronic circuit oscillation phenomenon disappears, then oscillation occurs on the segment or segments circuits. The key to this approach is to select capacitors that are suitable for capacitors, which can be used to compensate for interference signals. 

 

The method of breaking the circuit method is able to detect short circuit faults in electronic circuits effectively, which means that the fault area can be reduced by breaking the circuit, and the fault is determined. For example, if the electronic circuits using the regulated power supply, when will be a line connected to circuit current increases suddenly, existing in the circuit is connected to a short-circuit fault, at this time can be cut branch method locking short circuit position, if cut off a branch circuit when the current back to normal, explain the branch circuit. 

 

There are many methods of electronic circuit fault determination, some of which have some requirements on the equipment, and the application will be limited. Some of them may be low in equipment requirements, but they are also relatively low in efficiency. In practical application, we need to use and combine various methods to determine fault location, effectively and efficiently.