1. The resistance generated by alternating current on components is related to capacitance and inductance. When an electronic signal waveform is transmitted in a conductor, the resistance it experiences is called impedance.

　　2. Resistance is the resistance generated by direct current on components, which is related to voltage, resistivity, and current.

　　Application of characteristic impedance

　　1. The electrical performance provided by printed circuit boards for high-speed signal transmission and high-frequency circuits must be able to prevent reflection during signal transmission, maintain signal integrity, reduce transmission losses, and play a matching role. Only in this way can complete, reliable, accurate, worry free, and noise free transmission signals be obtained.

　　2. The size of impedance cannot be simply understood as better or better, the key is matching.

　　Control parameters of characteristic impedance