Learn about polyester capacitors in audio

With the development of technology, the scope of application of electronic components can be described as a wide range. In addition to our common film capacitors used in audio, in fact, polyester capacitors will also be used. Recently, Xiaobian saw a problem with a green 2A104J in the sound. Is this capacitor a filter capacitor? Can I measure good or bad with a digital multimeter? Then follow the progress of this article to solve the problem one by one.

2A104J, indicating that the capacitor is operating voltage 100V, capacity 0.1μF, error is plus or minus five percent, the current common is polyester capacitor. If this capacitor is used in parallel with the electrolytic capacitor in the power supply filter circuit, it is part of the filter capacitor to remove high frequency components in the power supply (the high frequency characteristics of the electrolytic capacitor are poor).

Usually use the 10K block of the multimeter to test and judge. The red and black test leads are respectively connected to the two poles of the capacitor (the capacitor needs to be discharged before each test), and the yaw of the hands is used to judge the quality of the capacitor. If the hands are quickly turned to the right and returned to the original position, the polyester capacitor is generally good. If the needle does not turn after swinging, the capacitor has broken down. If the hands are swayed back to a certain position and then stopped, the capacitor has leaked. If the hands do not move, the capacitor is open.

Due to the small capacity of the polyester capacitor, it is not easy to measure the available digital meter or capacitance meter with the pointer meter. Do you have an answer after reading this article?