In physics and electrical engineering, a conductor is an object or type of material that allows the flow of electrical current in one or more directions. For example, a wire is an electrical conductor that can carry electricity along its length.
In metals such as copper or aluminum, the movable charged particles are electrons. Positive charges may also be mobile, such as the cationic electrolyte(s) of a battery, or the mobile protons of the proton conductor of a fuel cell. Insulators are non-conducting materials with few mobile charges and support only insignificant electric currents.