Tests and experience capacitor oled module

1 fixed capacitors detection
A little less than 10pF capacitance detection
10pF capacitors due to the following fixed capacity is too small to measure with a multimeter, only qualitative check whether there is leakage, an internal short circuit or breakdown phenomenon. Measurement, the choice of a multimeter R × 10k block, respectively, with two tables document any two pins connected to the capacitor, the resistance should be infinite. If the measured resistance value (pointer to the right swing) is zero, then the capacitor leakage or damage to the internal breakdown. B detection 10PF ~ 001μF capacitor whether there is a fixed charge phenomenon, and thus determine its quality. Multimeter choose R × 1k block. Two transistors of the β values ​​are above 100, and the through current is smaller. Other models can be used 3DG6 composite pipe composed of silicon transistors. Multimeter red and black pen, respectively composite pipe and collector emitter e c phase. Because composite triode amplification, the measured capacitance charging and discharging process is amplified, so that the meter pointer swing rate increase, and thus easy to observe. It should be noted: In the test operation, especially in the smaller capacity measured capacitance, measured capacitance pin to repeatedly exchange contacts A, B two points can clearly see the multimeter pointer swing. C For more than 001μF fixed capacitance, available multimeter R × 10k block directly test whether the process of charging the capacitor and the presence of an internal short circuit or leakage, and according to the size of the pointer to the right to estimate the magnitude of the swing capacity of the capacitor.
(2) Detection of electrolytic capacitor
A Because of the electrolytic capacitor capacity is much greater than the average fixed capacitance, so measurements should be the appropriate choice for a range of different capacities. According to experience, the general case, 1 ~ 47μF capacitance between the R × 1k block can be measured, is greater than the capacitance of 47μF R × 100 block can be measured. 128x64 lcd display
B will then negative Multimeter red pen, black pen then positive, in the fourth year of the moment, the larger the meter pointer that is deflected to the right skewness (for the same electrical barrier, the greater the capacity, the greater the swing), then gradually turn to the left until it stops at a certain location. At this point the resistance is positive electrolytic capacitor leakage resistance, this value is slightly larger than the reverse leakage resistance. Practical experience shows that the electrolytic capacitor leakage resistance should normally be in the hundreds of kΩ or more, otherwise, it will not work properly. In the test, if the forward, reverse, no charging phenomenon that hands do not move, then disappear or internal circuit capacity; if the measured resistance is very small or zero, a large capacitor leakage or breakdown damage, can no longer be used. C For positive and negative signs of unknown electrolytic capacitors can be measured using the above method to determine the leakage resistance. That is, first measuring about any leakage resistance, remember its size, and then switching table pen then measure a resistance. Two measurements is the resistance of a large positive connection that time, namely the black pen then is positive, the red pen then is negative. D Use a multimeter power block, using a electrolytic capacitor, the reverse charge method, based on the size of the pointer swings to the right, you can estimate the capacity of electrolytic capacitors. lcm module
3 Detection of the variable capacitor
A gently rotating shaft, should feel very smooth and should not feel tight and sometimes loose even catching phenomenon. The axial load before and after, up, down, left, right, etc. pushed in all directions, the shaft should not be loose phenomenon. B rotating shaft with one hand, the other hand light touch the outer edge of the movable piece group should not feel any loosening. Contact between the shaft and the movable piece of poor variable capacitor, it can not continue to use. C place the multimeter R × 10k block, a hand two tables pen variable capacitors are connected to the movable piece and fixed terminals piece, the other hand to slowly rotating shaft few back and forth, multimeter pointer should In the infinity position does not move. In the rotating shaft in the process, if the pointer points to zero sometimes described movable piece and the short circuit between the stator; If you encounter a certain angle, meter reading is not infinite but a certain resistance, indicating that the variable capacitor Activity exists between the sheet and the stator leakage phenomenon.