Digital multimeter capacitance detection method
1, the detection of 10pF below the small capacitance due to 10pF below the fixed capacitor capacity is too small, with a multimeter for measurement, can only qualitatively check whether there is a leakage, internal short circuit or breakdown phenomenon. Measurement, you can choose the multimeter resistance file, with two pens were connected to any two pins of the capacitor, the resistance value should be infinity. If the measured resistance (pointer swing to the right) is zero, then the capacitor leakage damage or internal breakdown.
2, test 10PF ~ 0.01μF fixed capacitor whether charging phenomenon, and then judge its good or bad. Multimeter selected resistance block. Two transistor β value are more than 100, and penetration current to be some optional 3DG6 and other models of silicon transistor composite tube. The red and black pens of the multimeter are connected to the emitter e and collector c of the composite tube. Due to the amplifying effect of the composite transistor, the measured capacitance of the charge and discharge process to be amplified, so that the multimeter pointer swing amplitude increase, so as to facilitate observation. It should be noted that: in the test operation, especially in the measurement of smaller capacitance, to repeatedly switch the measured capacitance pin contact A, B two points, in order to clearly see the multimeter pointer swing.
3, for more than 0.01μF fixed capacitance, the multimeter can be used to directly test the capacitor with or without charging process and internal short-circuit or leakage, and can be based on the magnitude of the pointer to the right of the magnitude of the oscillation of the capacitor's capacity is estimated.
Inductor test
The multimeter will be placed in the resistance file, the red and black pens are connected to the colour code inductors of any lead, the pointer should swing to the right at this time. 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-coded inductor and the enameled wire used to wind the inductor coil diameter, the number of winding turns have a direct relationship, as long as the resistance value can be measured, it can be considered that the measured colour-coded inductor is normal.
