Conductor or conduction may refer to:

In physics:

In mathematics:

In physics and electrical engineering, a conductor is an object or type of material that allow the flow of electrical current in one or more directions. A metal wire is a common electrical conductor.

In metals such as copper or aluminum, the mobile 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 that support only insignificant electric currents.

Resistance and conductance

The resistance of a given conductor depends on the material it is made of, and on its dimensions. For a given material, the resistance is inversely proportional to the cross-sectional area; for example, a thick copper wire has lower resistance than an otherwise-identical thin copper wire. Also, for a given material, the resistance is proportional to the length; for example, a long copper wire has higher resistance than an otherwise-identical short copper wire. The resistance R and conductance G of a conductor of uniform cross section, therefore, can be computed as

Conductor (Cdr) is an appointment held by a few selected warrant officers class 1 in the Royal Logistic Corps and is one of the most senior appointments that can be held by a warrant officer in the British Army. Previously conductor was the most senior warrant officer appointment, but it was outranked with the creation of the Army Sergeant Major appointment in 2015 following Army reforms. The appointment was also reintroduced into the Royal Australian Army Ordnance Corps for selected warrant officers class 1 in 2005.

History

The first known mention of conductors is in the 1327 Statute of Westminster, when they are mentioned as the men whose job it was to conduct soldiers to places of assembly. The "Conductor of Ordnance" is mentioned in the records of the siege of Boulogne in 1544 and conductors are mentioned several times in surviving records from the 17th century. In 1776 they are described in Thomas Simes's book The Military Guide for Young Officers as assistants to the Commissary of Stores. The Land Transport Corps and the Military Stores Department of the 19th century both included conductors in their strength.