Conductors are called the substances having free carriers of the charged particles moving on all volume of material and thanks to it carrying electric current.
Characteristic of conductors
The conductor – the body carrying electric current. Distinguish conductors of the first and second sort. All metals and their alloys belong to conductors of the first sort. Water solutions of acids, salts and alkalis – the second. The body temperature is higher, the less it carries electric current, and, on the contrary, with decrease in temperature the conductivity increases.
Metals with high conductivity use for cables, wires, windings of transformers. Metals and alloys with low conductivity are applied in glow lamps, electric heaters, rheostats.
The key parameter characterizing the conductor – electrical resistance. It is expressed by the voltage drop relation in the conductor to the current proceeding on it and depends on ambient temperature. The conductor showing small resistance is considered good. For example, the aluminum conductor about section 2.5 square millimeter, passes charged particles much less, than the copper conductor in 2.5 square millimeters diameter. When pass current through each of them with a current of 25 amperes (5.5 kilowatts), the copper conductor strongly heats up while aluminum heats up so that melts isolation around itself. In that case, if there is no automatic protection, there is a short circuit.
Application of conductors
Conductors use for grounding of electroinstallations. As the grounding conductors and ground wires use metal designs of constructions and buildings, observing at the same time continuity and conductivity of a chain. For the grounding conductors use usually steel. If flexible crossing points and in other cases are necessary, apply copper. Conductors can be also used for alignment of potentials. It plays a special role in livestock rooms where practically always crude floors and a large number of the grounded metalwork of various type. Animals touch metal surfaces standing on a damp surface, thereby receiving electric impulses. The livestock production becomes inefficient because of low milking capacity of cows. Undesirable consequences prevent, leveling potentials of a surface of a floor and metal designs, by laying of the grounded round steel conductors. Conductors use in the lightning rod, taking away a lightning to the earth that it did not put any damages. There are conductors with a high specific resistance which resistant to oxidation. Such materials apply in electric heaters, they have high plasticity and can be extended in a thin wire and be rolled out in a foil. One of such the conductor is aluminum.