two-wire circuit

electronics

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Last updated

July 14, 2026

Quick Summary

A two-wire circuit, also known as an open-wire pair, is a system used in telecommunications that employs a pair of conductors to provide both a forward and return path for electric current. This design helps to minimize interference from external sources like lightning because the two wires run in parallel and are equidistant from the interference source, causing any induced currents to cancel each other out at the receiver.1

An electric circuit, in general, is a path for transmitting electric current. It includes a power source (like a battery or generator), components that use the current (like lamps or motors), and the connecting wires. Circuits can be direct-current (DC) or alternating-current (AC), and can be arranged in series (components in a single path) or parallel (components in separate branches).2

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telephone
From single-wire to two-wire circuits
…by the use of a two-wire, or “metallic,” circuit; the first demonstration of such a system occurred in 1881 on a telephone line between Providence, Rhode Island, and Boston.
Read More
…by the use of a two-wire, or “metallic,” circuit; the first demonstration of such a system occurred in 1881 on a telephone line between Providence, Rhode Island, and Boston.
Read More