How to use a digital multimeter to check the points of fault in the line
1. Appearance inspection.
You can touch the battery, resistor, transistor, and integrated block with your hands to see if the temperature rise is too high. If the newly installed battery becomes hot, the circuit may be short-circuited. In addition, the circuit should also be observed for disconnection, desoldering, mechanical damage, etc.
2. Waveform analysis.
Use an electronic oscilloscope to observe the voltage waveform, amplitude, period (frequency), etc. of each key point in the circuit.
For example, if you test whether the clock oscillator is starting to oscillate, if the oscillator has no output, it means that the internal inverter is damaged, or the external component may be open circuited.
3. Measure component parameters.
For components within the fault range, conduct online or offline measurements and analyze parameter values. When measuring resistance online, the influence of components connected in parallel with it should be considered.
4. Hidden troubleshooting.
Hidden fault refers to the fault that appears and disappears, and the instrument is good and bad sometimes. This type of failure is relatively complex, and common causes include weak solder joints, loose joints, loose connectors, poor contact of the transfer switch, unstable component performance, and continuous breakage of leads. In addition, it also includes some external factors. Such as the ambient temperature is too high, the humidity is too high or there are intermittent strong interference signals nearby, etc.
5. Detect the working voltage at all levels.
Detect the working voltage at each point and compare it with the normal value.
First of all, the accuracy of the reference voltage should be ensured. It is best to use a digital multimeter of the same model or a similar one for measurement and comparison.
Just measure and compare the values. The multimeter measurement method refers to the method of using a multimeter to measure the voltage, current, and resistor values in a circuit to determine faults.
Multimeter, also known as multiplex meter, multimeter, three-purpose meter, multimeter, etc., is an indispensable measuring instrument in power electronics and other departments. It is generally used to measure voltage, current and resistance as its main purpose. Multimeters are divided into analog multimeters and digital multimeters according to their display modes. It is a multi-functional, multi-range measuring instrument. Generally, a multimeter can measure DC current, DC voltage, AC current, AC voltage, resistance and audio level. Some can also measure AC current, capacitance, inductance and semiconductor. Some parameters (such as β), etc.
