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As an indispensable part of our daily electrical components, capacitors are widely used in isolation, coupling, bypass, filtering, tuning loops, energy conversion, control circuits and so on. Most of the causes of electrical product damage may be caused by capacitor damage, so how do we test the quality of the capacitor?
Before measuring the capacitor, be sure to discharge the capacitor. After removing the capacitor, short-circuit both ends of the capacitor.
Look at the capacitance of the capacitor tag capacitor to select the appropriate gear. Let's take run capacitor as an example.
Turn the multimeter to the capacitor position, the gear position should be larger than the capacitance value on the capacitor label. We choose 200 microfarad.
Press the multimeter measurement button, which is usually labeled “Cx/Lx”, which is the measurement capacitor button. When pressed, the display will prompt.
Note that the test leads must be installed in both the COM and Cx jacks.
Finally, the two probes are used to contact the two ends of the capacitor. Generally, the measured value will be too large, but as long as the value is close to the label, the capacitor is normally available.
In summary, measuring capacitors are usually available in the following ways:
Method / step:
Pointer multimeter resistance file check the quality of the electrolytic capacitor:
This method is suitable for electrolytic capacitors with a low withstand voltage, such as 6V or less. First, turn the pointer multimeter to the resistance file, the gear position is R*1k file, then connect the red test pen to the negative pole of the capacitor, and the black test pen is connected to the positive pole. Pay attention to the pointer change of the multimeter while connecting. The pointer will oscillate and then return to zero scale, or near it, after discharge. A bounce to restore the zero proves that it is good, and vice versa.
The digital multimeter diode file checks the quality of the electrolytic capacitor:
This method is suitable for the case where the electrolytic capacitor is broken down. Put the digital multimeter in the diode file and connect the two test leads to the two ends of the electrolytic capacitor. At this time, pay attention to whether the digital multimeter emits a "drop" sound. If not, it proves that it is good, no Being penetrated.
Capacitance direct test method:
On some powerful digital multimeters, there is a capacitance test position. When we dial the capacitance test position, the red pen is connected to the positive pole and the black test pen is connected to the negative pole. If infinity occurs, the capacitor is open-drain and open; when it is measured to be zero, this indicates that it has been broken. The normal range number is normal.
Resonance method:
We use the LC resonant circuit to observe the data. If the data is wrong, or the waveform is wrong, the capacitor is broken.
To sum up:
Regardless of the method used, we use the basic principle of the capacitor to monitor it. It is wrong to distinguish it from its basic properties.
Precautions:
Pay attention to the connection between the test leads and the capacitor.including run capacitor
