In the world of electronic components, the normal operation of capacitors is crucial for all kinds of electronic equipment. As a powerful tool in the hands of electronic engineers and enthusiasts, a multimeter can help us test the status of capacitors quickly and effectively. Today, MobikeChip will bring you an in-depth understanding of how to use the multimeter to test capacitors.
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Multimeter Selection and Preparation: Opening the Door to Accurate Testing
There are many kinds of multimeters with different functions, in order to test capacitors accurately, you must first choose the right multimeter and make preparations. For general capacitor testing, an ordinary digital multimeter can meet the basic needs of its capacitance measurement function is more commonly used and easy to operate. However, if it involves high precision or special types of capacitors, such as ceramic capacitors, tantalum capacitors, etc., professional multimeters with higher precision and more measurement functions are more suitable.
After selecting a multimeter, make sure that it is fully charged and the display is clear and trouble-free. Check whether the pen is intact, the pen plug and the multimeter jack connected tightly, to avoid poor contact during the test. Set the multimeter range knob to the capacitance measurement gear, the capacitance measurement range of different multimeters is different, according to the nominal capacitance value of the capacitor to be tested roughly the range of the initial estimate, select the appropriate range, so that the measured value as far as possible in the middle of the range area, which can maximize the assurance of the measurement accuracy for the subsequent precision testing to build a solid foundation.
Capacitance Measurement: Directly Hitting the Core Performance Indicators
Capacitance value is a key characteristic of capacitors, and the measurement of capacitance value with a multimeter can initially determine whether it is good or bad. For non-polarized capacitors, such as common ceramic capacitors, mica capacitors, etc., the two pens of the multimeter can directly contact the two pins of the capacitor. The operation process should be gentle to avoid damage to the pins. Read the value shown on the multimeter display, due to the existence of a certain precision error capacitors, the actual measured value and the nominal value of a slight deviation is normal, as long as the capacitor is within the nominal accuracy, can be judged capacitance is basically normal. For example, a nominal value of 22nF, accuracy of ±10% of the ceramic capacitor, the actual measured value between 19.8nF and 24.2nF, can be regarded as qualified.
For capacitors with polarity such as electrolytic capacitors, it is necessary to pay extra attention to the polarity when measuring. Connect the positive terminal of the multimeter to the positive terminal of the capacitor and the negative terminal to the negative terminal. Reversing the connection may not only lead to inaccurate measurement results, but also damage the multimeter or the capacitor. Correctly connected, read the measured value, the judgment method is similar to the non-polarized capacitor. If the measured value and the nominal value deviation is too large, or even infinite or close to zero, it indicates that the capacitor may have an open circuit, short circuit or serious degradation of performance and other issues, need to be further in-depth investigation.
The capacitor leakage detection: to uncover potential hidden dangers
Capacitor leakage will have a serious impact on its performance and circuit stability, the multimeter can also help us to help detect this hidden danger. The multimeter range knob to the resistance measurement of the high resistance gear, generally MΩ level. For non-polarized capacitors, the pen is connected to the same way as the capacitance value measurement, measurement and observation of the multimeter display resistance value. Under normal circumstances, just contact moment, the multimeter pointer (or digital display) will have a short jump, and then quickly tend to infinity, this is because the capacitor in the charging process will have a short current through the charging process should be no current after the completion of charging, that is, the resistance is infinite. If the measurement process resistance value is always small, stable and does not rise to infinity, indicating that the capacitor leakage phenomenon.
For electrolytic capacitors, due to its internal structure characteristics, leakage detection method is slightly different. First use the meter pen to short the capacitor poles for discharge, eliminate the residual charge, and then connect the meter pen according to the correct polarity, observe the resistance value change. Similarly, the normal electrolytic capacitors in the charging is completed resistance should tend to infinity, if there is a leakage, the resistance value will be significantly smaller, and over time there may be a slow change, which means that the capacitor in the use of the process will consume additional electrical energy, may cause circuit failure, need to be careful.
The charging and discharging characteristics of the observation: insight into the inner workings of the state
Charging and discharging characteristics of capacitors is also an important basis for judging their strengths and weaknesses, the multimeter can indirectly show this process. After the measurement of capacitance value is completed, keep the meter pen connected to the capacitor and observe the change of the multimeter display value. For normal capacitors, when the meter pen just contact, the multimeter will display a charging current corresponding to the resistance value, with the charging process, the value will gradually increase until it tends to infinity, which indicates that the capacitor is charging normally. After that, the pen will be adjusted, the capacitor began to discharge, the multimeter will display the value of the rapid decrease from infinity, showing a reverse current change process.
By observing this charging and discharging process, we can further understand the working status of the capacitor. If the charging process is slow, the value of the change is not obvious, or discharge no obvious value change, are implied that the capacitor may have problems, such as internal plate aging, excessive dielectric loss and so on. This method of observing the charging and discharging characteristics through a multimeter gives us another insight into the intrinsic quality of a capacitor, and aids in determining whether it can work stably and reliably in a circuit.
At MobikeChip, we not only provide high quality capacitor products, but also focus on teaching you professional electronic component knowledge and testing skills. Mastering how to test capacitors with multimeter will help you to be more skillful in electronic design, debugging and repairing. If you encounter any problems in capacitor testing, selection or application, please feel free to visit MobikeChip website, our professional team will be happy to answer your questions.
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