The ceramic filter is made of lead zirconate titanate ceramic material. This ceramic material is made into a sheet and coated with silver on both sides as electrodes. After being polarized by DC high voltage, it has a piezoelectric effect. It plays the role of filtering, has the characteristics of stability and good anti-interference performance, and is widely used as a frequency selection component in various electronic products such as TV sets, video recorders, and radios. It has the advantages of stable performance, no adjustment, and low price, replacing the traditional LC filter network.