Speaker terminals are electrical connectors that can be used to wire together different types of audio equipment. The term "speaker terminal" is often used in reference to spring clips, though many other types of connections are commonly used as well. Binding posts, banana plugs and Radio Corporation of America (RCA) jacks are all commonly found in home audio equipment, and car speakers often have spade terminals. In most cases, each speaker terminal can accept one wire that is either the positive or negative side of a speaker circuit. RCA connectors are an exception, as those cables contain both a positive and negative wire in a single sheathe.
In order to connect audio components such as speakers, amplifiers and receivers, speaker wire is commonly used. These wires are typically insulated and paired, since both negative and positive connections are required to complete a circuit. Rather than having one single way to connect these wires to audio components, a number of different methods are used. In some cases, the bare wire is used as a terminal connector, while in other situations special terminal connectors can be attached. RCA cables can also be used with certain audio components, and some small speakers even use wires that come with tip ring sleeve (TRS) connectors.
The simplest method of wiring an audio system involves a speaker terminal known as a spring clip. These terminals are designed to be used with bare wire, so it is unnecessary to crimp or solder any special connectors. Each component in an audio system that uses this type of speaker terminal has at least two of them, and they are usually color coded black and red for negative and positive. One side of the spring clip can be depressed, which allows a length of bare speaker wire to be inserted.
Binding posts are another common variety of speaker terminals that can be used with bare wire, though they are also compatible with a few other types of connectors. A binding post consists of a threaded stud that typically has a captive metal nut inside a color coded plastic knob. Bare wire can be wound around one of these studs and then tightened into place with a nut, though it is also possible to solder or crimp a spade terminal on for a more reliable connection. Most binding posts also have a central jack that can accept banana plugs, which can also be permanently attached to speaker wires.
Car audio systems sometimes use RCA jacks, though spade terminals are common. This type of speaker terminal is typically just a flat, rectangular protrusion that a spade connector can slide onto. In most cases, the smaller of the two is the negative terminal, though that is not always the case. If the identity of the negative terminal is in question, it is always safest to check with a low voltage battery before connecting up to an audio system.