A few tips for troubleshooting digital multimeters
It is a multi-purpose electronic measuring instrument, which generally contains functions such as ammeter, voltmeter and ohmmeter. Compared with the pointer multimeter, the digital multimeter has the advantages of high accuracy, speed, large input impedance, digital display, accurate reading, strong anti-interference ability, and high degree of measurement automation and is widely used. However, if not used properly, it is easy to cause failure.
Digital multimeter troubleshooting should generally start from the power supply. Digital multimeter troubleshooting can be carried out in the following ways.
1, appearance check.
You can touch the battery, resistor, transistor, integrated block temperature rise is too high. If the newly installed battery is hot, the circuit may be short-circuited. In addition, it should also observe whether the circuit is broken, desoldering, mechanical damage and so on.
2, waveform analysis.
With an electronic oscilloscope to observe the circuit voltage waveform, amplitude, period (frequency) and so on.
For example, such as measuring whether the clock oscillator vibration, if the oscillator has no output, indicating that the internal inverter is damaged, may also be an external component open circuit.
3, measuring component parameters.
Components within the scope of the fault, online measurement or offline measurement, parameter values should be analysed. For resistance online measurement, should consider the impact of the components connected in parallel with it.
4, hidden fault elimination.
Hidden fault refers to the fault is hidden, the instrument is sometimes good and sometimes bad fault. Such failures are more complex, common causes include solder joints, loose, loose connectors, poor contact with the transfer switch, component performance is unstable, the lead will be broken and so on. In addition, also includes some external factors caused by. Such as high ambient temperature, excessive humidity or intermittent strong interference signals nearby and so on.
5, detect the working voltage at all levels.
Detect the working voltage at all points, and compare with the normal value, first of all, the accuracy of the reference voltage should be guaranteed, it is best to use a piece of the same model or similar digital multimeter for measurement and comparison.
