In the process of maintenance and overhaul of electronic equipment, how to check capacitor is a crucial link. It as electronic circuits in the basic components, the stability of its performance is directly related to the working state of the entire circuit. Therefore, mastering the correct detection method is important for timely detection and resolution of potential problems to ensure the stable operation of the circuit.
How to check capacitor
Four kinds testing methods
1.Multimeter test method
For fixed capacitors above 0.01μF, you can use the multimeter Rx1k block to test. This method determines the performance by observing the oscillation of the multimeter pointer. During the test, first touch the two pins of the condenser with two pens, and then switch the pens to touch once. If normal, the multimeter pointer will first swing to the right, and then quickly to the left back to infinity position. The larger the capacitance, the larger the amplitude of the pointer swing. If the pointer never swings, the capacitor’s capacity is lower than 0.01μF or has failed. If the pointer can not return to infinity after swinging, it indicates that the capacitor has a leakage or breakdown phenomenon.
2.Fuse simple test method
The fuse (fuse current rating according to the condenser capacity to determine) and the condenser to be tested in series with 220V AC power supply. If the fuse blown, indicating that the capacitor internal short circuit. If the fuse does not blow, after charging cut off the power supply, with an insulated screwdriver to the condenser poles short circuit discharge. If a spark occurs, the condenser is normal; otherwise, it indicates that the capacitor capacity becomes small or open circuit. This method needs to be repeated several times to draw accurate conclusions.
3.Incandescent light bulbs in series test method
Incandescent bulbs and condenser in series with 220V AC power supply. If the brightness of the bulb is slightly darker than directly connected to the power supply, indicating that the condenser is normal; if the bulb is not bright, indicating that the condenser internal circuit; if the brightness of the bulb is the same as directly connected to the power supply, indicating that the condenser internal short circuit.
4.Megohmmeter test method
Use megohmmeter (250V level) for testing. Shake the handle, such as the pointer points to infinity, indicating that the capacitor internal circuit; such as the pointer points to zero, indicating that the condenser internal short circuit. In addition, you can also carry out the condenser through the ground test, the megohmmeter terminals were connected to the condenser terminals and shell, shake the handle, such as the pointer points to zero, said the condenser through the ground.
5.Capacitor capacitance measurement (additional methods)
In the absence of a special instrument, you can use a multimeter to measure the capacitance.Specific steps are: the fuse (specifications according to the condenser capacity to determine) and condenser to be measured in series with 220V AC power supply. Use the multimeter AC voltage gear to measure the voltage at both ends of the capacitor U, use the multimeter AC current gear to measure the current through the capacitor I. According to the formula I = U/XC and XC = 1 / (2πfC), where f is the frequency of the alternating current,the capacitor’s capacitance can be calculated C = 3.18 × (I / U) (microfarads).
Understanding how to check capacitor is critical to ensuring the stability and performance of electronic circuits. With the detailed testing methods described above, we are able to accurately assess the condition, identify potential problems and repair or replace them in a timely manner. These testing methods are not only practical but also easy to follow and are an integral part of maintaining the proper operation of electronic equipment.
