An anode is a positively charged electrode toward which electrical current flows in a circuit.
In electrical and electrochemical systems, an anode is the point where electrons exit a device or material and where oxidation reactions typically occur. It serves as the electrode that attracts negatively charged particles, known as anions, while repelling cations (positively charged ions). The direction of current, by conventional definition, flows toward the anode from the external circuit.
In commercial and industrial electrical systems, anodes play a vital role in a wide range of equipment including power supplies, batteries, electrolytic cells, cathodic protection systems, and electroplating operations. Understanding the function of anodes is essential in contexts where current flow, material degradation, and corrosion resistance are critical concerns.
Anodes may be composed of a variety of conductive materials depending on the application, ranging from metals like zinc and aluminum in corrosion-control systems, to graphite or specialized alloys in high-performance electrical assemblies. In direct current (DC) systems, the anode remains fixed as the positive terminal, while in alternating current (AC), the role of the anode can alternate depending on the direction of the current.
The term “anode” was introduced in the 19th century by scientist Michael Faraday during his foundational research in electrochemistry. Derived from the Greek word anodos, meaning “way up” or “path,” it was used to describe the direction in which current appeared to enter an electrical device. Faraday's naming conventions remain foundational in modern electrical engineering terminology.