电容好坏的测量

电容好坏的测量 Measurement of the quality of capacitors.Txt Measurement of capacitance Capacitors, good or bad There are 4 kinds of capacitor damage: 1. short circuit, 2. non capacity, 3. capacity reduction, 4. stability 1. needless to say 2. filter according to the voltage and the phenomenon of 3. experience the most difficult to estimate the equivalent capacity must also consider the time factor of 4. most associated with the leakage of peeling bulging head phenomenon, the thermal stability of poor cooling is a good way to use alcohol The quality of the capacitor is really bad for the road. Most of the actual operation of capacitor breakdown, leakage current, stability is not good from the appearance or temperature Shenglai judgment, sometimes using the electrical measurement to confirm the voltage; for large capacitance circuit, first through the analysis of the failure phenomena and circuit, suspected remove measurement, small capacitor number by and connected to the test judge. It's OK to use a digital watch or a capacitor meter, but it's better to replace it directly. Sometimes it's good but it doesn't work. Pointer table X10K ohm gear measurement, pointer swing slightly, and then point to infinity. Sometimes the measurements are normal, but they are not available on the computer. It's better to test with a capacitor meter, but not with a universal watch! The model is pps512j 1600V and the other is 822j pp800v You should pay attention to pressure: you are the first 1600 Volts 5100 micro method 800 Volts 8200 micro method You'd better replace it. If the circuit requires high voltage, it must not be too small You can also use a multimeter to compare the same capacitance, see if the pointer swings, the biggest resistance. First of all, you can see whether the capacitor has no drain or capacitor, and there is no upward convex, which is the most direct method, if not. Replace or replace with a capacitor. When replacing, pay attention to the size of the pressure and capacity. Digital multimeter can test the capacity of the capacitor, but the soft breakdown is not measured. It can be checked by the resistance tester and the best way to replace it How small chip capacitors judge good or bad? Method 1. The resistance of the general small chip capacitor is infinite, and the resistance is abnormal. The volume becomes smaller, the multimeter cannot measure, and the direct replacement. Method two, a safe way, with a multimeter of the second pole of a needle to the ground, the other needle measuring capacitor at both ends of both ends of the ring, indicating short-circuit Three, if the small patch capacitor short circuit with a multimeter measurement can be judged, if it is open, because the capacity is too small, use a multimeter is not out of line with a pencil from 220V, the chip capacitors in pencil pins on the cap, the neon bulb to see whether light emitting capacitor is good, otherwise the circuit breaker. 220V voltage, don't in the experiment, too late to cry Method four, the resistance is infinite, the resistance is zero, the call is bad. Others should have some small changes 1. the most accurate is to solder down and measure its capacity with a digital capacitor meter! 2. no digital capacitor meter, solder down, with mechanical meter 10K file measurement, a little bit of swing can be shown as normal! 3., in the road, then use a digital meter or mechanical meter to measure its resistance, if the resistance is zero, it is necessary to solder down to further determine! 1. detection of fixed capacitors A detects small capacitances below 10pF. Because the fixed capacitor capacity below 10pF is too small, it can only be qualitatively checked for its leakage by measuring with a multimeter, Internal short-circuit or breakdown. When measurements can be used multimeter R * 10K block, two pin two probes are respectively arbitrary capacitance, resistance should be infinite. If the resistance is measured (the pointer swings to the right) to zero, then the leakage of capacitance or internal breakdown is explained. B detects whether there is charging phenomenon in 10PF ~ 001 F fixed capacitor, and then judges whether it is good or bad. The multimeter uses R * 1K block. The beta values of the two transistors are above 100, and the penetration current is small. 3DG6 and other types of silicon triode can be used as a composite tube. Multimeter red and black pen respectively with the composite pipe emitter and collector e c. Because of the amplifying function of the compound triode, the charging and discharging process of the measured capacitor is enlarged so that the pointer of the multimeter is enlarged, so as to be convenient for observation. It should be noted that in the test operation, especially when measuring the smaller capacity of the capacitor, it is necessary to repeatedly change the measured capacitor pin, contact A, B two points, you can clearly see the pointer of the multimeter swing. C for the fixed capacity of more than 001 F, multimeter R * 10K block has no direct test of capacitor charging process and there is no internal short-circuit or leakage, and can be estimated according to the capacity of the capacitor size range of the pointer to the right swing. 2. detection of electrolytic capacitors A because the capacity of electrolytic capacitor is much larger than that of general fixed capacitor, the proper range should be chosen according to different capacity. According to experience, in general, the capacitance between 1~47 F can be measured by R * 1K barrier, and capacitance greater than 47 F can be measured by R * 100 block. B the multimeter is connected to the anode of the red pen, the black pen is connected with the positive pole, just in the moment of contact, the multimeter is right skewness (large deflection pointer for the same electric barrier, the bigger swing is larger), then gradually turn to the left, until stopped at a certain position. The resistance at this point is the forward leakage resistance of the electrolytic capacitor, which is slightly larger than the reverse leakage resistance. Practical experience shows that the leakage resistance of electrolytic capacitors should generally be above several hundred K ohms, otherwise it will not work properly. In the test, if there were no positive and negative charge of the phenomenon, the hands do not move, the capacity to disappear or internal circuit; if the measured value is very small or zero, indicating large capacitor leakage or breakdown, can not be used again. C an electrolytic capacitor with unknown positive and negative signs can be identified by the method of measuring leakage resistance. To check any leakage resistance, remember the size, and then measure the resistance of a pen exchange. The first two large resistance in the measurement would be a positive connection, namely black pen then is positive, then the red pen is negative. D uses the multimeter resistor block, uses the positive and reverse charging method to the electrolytic capacitor, according to the size of the swing amplitude of the pointer to the right, can estimate the capacity of the electrolytic capacitor. 3. detection of variable capacitors A with rotating shaft gently, feeling very smooth, sometimes even should not feel the tight loose hysteresis phenomenon card. When the axle is forward, backward, upper, lower, left, right and other directions, the rotating shaft should not be loose. B with a hand rotating shaft, the other hand touch moving outer tablet group, should not feel any loose phenomenon. The variable capacitor which is not in contact with the rotor and the rotor plate can not be used any further. C Multimeter in R * 10K block, the rotor and stator end leads to a hand the two probes are respectively connected variable capacitors, on the other hand will slowly rotating shaft a few back and forth, the multimeter pointer should not move in infinite positions. In the process of rotating shaft, if the pointer sometimes point to zero, so the dynamic short circuit between tablets and tablets; if there is a certain angle, the multimeter reading was not infinite but had a certain resistance, indicating the existence of leakage between rotor and stator variable capacitor. (above for reprint)