Pointer multimeter for testing electrolytic capacitors
1,Because the capacity of electrolytic capacitor is much larger than that of general fixed capacitor, therefore, when measuring, we should choose suitable range for different capacity. According to the experience, in general, the capacitance between 1～47μF can be measured by R×1k, and the capacitance greater than 47μF can be measured by R×100.
2, the multimeter red pen to the negative pole, the black pen to the positive pole, in just the moment of contact, the multimeter pointer that is to the right of the larger deflection (for the same resistance block, the larger the capacity, the larger the amplitude of the pendulum), and then gradually turn back to the left until it stops at a certain position. At this time the resistance value is the forward leakage resistance of electrolytic capacitors, this value is slightly larger than the reverse leakage resistance. Practical experience shows that the leakage resistance of electrolytic capacitors should generally be more than a few hundred kΩ, otherwise, it will not work properly. In the test, if the positive and reverse are not charging phenomenon, that is, the needle does not move, it means that the capacity disappears or internal disconnection; if the measured resistance is very small or zero, it means that the capacitor leakage is large or has been damaged by breakdown, can not be used again.
3, for positive and negative signs unknown electrolytic capacitors, can use the above method of measuring leakage resistance to identify. That is, the first arbitrary measurement of leakage resistance, remember its size, and then exchange the pen and then measured a resistance value. Two measurements in the resistance value of the large one is the positive connection, that is, the black pen is connected to the positive pole, the red pen is connected to the negative pole.
4, the use of multimeter resistance block, the use of electrolytic capacitors for positive and negative charging method, according to the pointer to the right of the amplitude of the magnitude of the swing, you can estimate the capacity of the electrolytic capacitor.
Inductor detection
The multimeter will be placed in the resistance file, the red and black pens are connected to any of the color-coded inductor lead, the pointer should swing to the right. According to the size of the measured resistance value, can be specifically divided into the following three cases for identification:
1, the measured resistance value of the colour code inductor is zero, its internal short-circuit failure.
2, the size of the measured DC resistance value of the colour code inductor and winding inductor coil used in the enamel wire diameter, the number of winding circle has a direct relationship, as long as the resistance value can be measured, it can be considered that the measured colour code inductor is normal.
