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How to detect the filter correctly?

Date:2022-11-15 16:24:00 Views:130

In engineering, according to the requirements of the output port on the signal frequency range, a special network is designed and placed between the input and output ports to enable the required frequency components of the output port to pass smoothly, while suppressing or weakening the unwanted frequency components. This kind of intermediate network with frequency selection function is called a filter in engineering. The following is a brief analysis of the detection filter for your reference.

Filter circuits have many practical applications in electronic design. For example, in the case of DC power supply, the filter can be used to eliminate the high-frequency noise caused by the AC circuit, and can smooth the DC voltage output by the rectifier. In radio communication, a filter enables the radio to provide only the signals needed by the listener, while shielding other signals. Similarly, the filter enables the radio transmitter to generate only one signal while weakening other signals that may interfere with the radio transmitter.


When the filter fails, it often causes the outdoor unit to work unstably or not. During detection, the input and output voltages of the filter shall be checked to determine the fault point. The method is: short circuit the two pins of the capacitor to discharge, and connect the black probe of the multimeter to the positive pole of the electrolytic capacitor. The red probe is connected to the negative pole (for a pointer multimeter, the probe is intermodulated when measuring with a digital multimeter). In normal conditions, the probe should swing in the direction of low resistance first, and then gradually return to infinity. The greater the swing amplitude of the meter needle or the slower the return speed is, the greater the capacity of the capacitance is. On the contrary, the smaller the capacity of the capacitance is. If the meter needle does not change at some place in the middle, it indicates that the capacitance leaks. If the resistance indication value is very small or zero, it indicates that the capacitance has broken through the short circuit. Since the battery voltage used by the multimeter is generally very low, it is more accurate to measure the capacitance with low withstand voltage. When the withstand voltage of capacitance is high, although the measurement is normal, leakage or breakdown may occur when high voltage is applied.

The above is about the filter detection organized by the wound core detection team, and I hope it will be helpful to you. Chuangxin Testing is a professional testing agency for electronic components. At present, it mainly provides integrated circuit testing services such as capacitance, resistance, connector, MCU, CPLD, FPGA, DSP, etc. Specializing in electronic component function testing, electronic component incoming appearance testing, electronic component dissection testing, acetone testing, electronic component X-ray scanning testing, ROHS component analysis testing. Welcome to call, we will serve you wholeheartedly!