如何判断电容的容量、正负极、好与坏（How to judge capacitance capacity, positive and negative poles, good and bad）.doc

如何判断电容的容量、正负极、好与坏（How to judge capacitance capacity, positive and negative poles, good and bad） 1. Check the quality of electrolytic capacitor with Multimeter The two lead electrolytic capacitors with positive and negative, in the examination of its quality, the electrolytic capacitor low voltage (6V or l0V), the resistance profile should be placed in the R or R * 100 * 1K file, the negative end of the red pen is connected with the capacitor, the black probe connected to the positive terminal. When the pointer multimeter will swing, then return to zero or near zero. Such electrolytic capacitors are good. The greater the capacity of the electrolytic capacitor, the longer the charge time, the slower the pointer swings. 2. Judge the positive and negative lead of electrolytic capacitor by multimeter Some low voltage electrolytic capacitor, if the positive and negative lead mark is not clear, according to its positive current, leakage current is small (resistance value is big), reverse current leakage current characteristics to judge. The specific method is: Contact capacitor with red, black pen two lead, remember the leakage current (resistance) size (indicated by the pointer swing back and stop the resistance), then this capacitor, negative lead short answer, the red and black pen on after the leak current. By showing the value of leakage current as the standard to judge, the fuse contact with the black pen is the end of the electrolytic capacitor. This method is very difficult to distinguish the polarity of the electrolytic capacitor because of its small leakage current. 3. Use a multimeter to check the variable capacitor A variable capacitor stator and a set of dynamic slices. With a multimeter resistance profile can check whether the touch between it and tablets, with red and black pen are respectively connected with the rotor and stator, rotating shaft handle, the meter pointer does not move, so the dynamic, short between tablets (touch tablets); if the pointer swi