The rca audio plug is the most common daily use. There is a standard plug at both ends of the wire. There is a male terminal in the center, surrounded by a ring. This ring is sometimes discarded for flexibility. The device is equipped with a socket, and there is a small hole in the center surrounded by a metal inner ring. The diameter of the outer ring of the socket is smaller than that of the plug to allow the plug to be firmly inserted. The socket is filled with an insulator between the inner and outer rings, usually with plastic. Compared with other types of terminals, RCA terminals are used for different purposes, including as power terminals, radio terminals, and speaker wire terminals. It is very popular as a terminal for composite video, but its impedance matching performance is poor. RCA terminals and cables are also commonly used to transmit SPDIF digital audio, distinguished by orange plugs, also known as "coaxial cables." The connection method is to push the plug into the socket of the device (commonly known as female).
The signal transmission needle protrudes from the plug. Usually, the needle is in contact with the socket before the grounding ring of the two parties (referring to the device and the plug) touches, and it will make a buzzing or chirping sound when connecting the activated sound device. If the plug is half dropped (the ground is broken but the signal is not broken), a continuous noise will be emitted. In addition, for some plugs, especially the cheapest ones, the tightness and effectiveness of the grounding sheath will be greatly reduced. RCA plugs are often distinguished by color. Yellow is used for composite video. In analog stereo audio, white (or black) is used for the left channel and red is used for the right channel. "Yellow, white and red" these jacks almost all audio-visual equipment are also installed. There is at least one "yellow, white, and red" jack on the TV for connecting to a camcorder (through the 3.5 mm mini TRS terminal to three RCA terminals, also known as "mini RCA"), digital cameras and home game consoles. Although almost all audio-visual terminals, including audio, composite and component video, and SPDIF digital audio, can be used with wires with a resistance of 75 ohms, there are some special-purpose rca audio plug wires on the market that have higher resistance.