A balanced input is a type of electrical connection that uses three conductors, typically two signal wires and one ground, to reduce noise and maintain signal integrity over longer distances.
Balanced input technology is widely used in commercial AV, broadcast, and communications systems where signal quality is critical. It employs two signal conductors carrying identical signals with opposite polarity, along with a separate ground or shield. At the receiving end, any electromagnetic interference (EMI) picked up along the cable is canceled out because it appears equally on both conductors. This design enhances noise rejection and improves reliability over long cable runs. Balanced inputs are often paired with twisted pair cabling, which provides tight conductor coupling to further minimize interference. They are commonly found in microphones, audio processors, video transmitters, and industrial control equipment.
Balanced input applications align with design principles and standards from AES (Audio Engineering Society), EIA (Electronic Industries Alliance), and TIA (Telecommunications Industry Association).
Balanced connections originated in early telephone and telegraph networks to combat noise over long distances. The method later became integral to professional audio, broadcast, and industrial systems, where clean signal transmission remains essential.