Conductors
"Substances with a plurality of free electrons are called conductors." Of these, the electric current flows smoothly. Their atoms have one, two or three connective electrons in their final orbit. Most metals are conductors, such as silver, copper, Gold, aluminum etc.
Properties of a Good Conductor
A good conductor should have the following qualities -
(i) Cheap - The driver should be cheap so that it can be used for general electrical works.
(ii) Easily available - The driver should be easily available so that it can be used for general electrical works.
(iii) Tensile conductors should be ductile so that its fine wires can be pulled which can be used in winding operations like choke, armature etc.
(iv) tough- The driver should be tough so that the wires made from it can be used in the overhead line and do not break easily when pulled.
(v) Impairment - The driver should be malleable so that sheets and leaves can be made as required.
(vi) Stitchable - The tin-lead solder can be soldered on the driver to provide strength and durability to its wire joint.
(vii) Low Specific Resistance - The specific resistance of the driver should be reduced so that the voltage drop and electric power consumption are reduced.
(viii) Free from the effects of the environment: The driver should be such that he is unaffected by the effects of the environment like moisture, rain, sun, etc.
Principal of Conductors
The conductors used in electrical works are as follows:-
(i) Silver: It is white, tensile, malleable and of low specific resistance. Being valuable, it is used to make contact points for relays, contactors, starters etc.
(ii) Copper: It is metallic - red, ductile, traumatic and of low specific resistance. It is cheaper than silver and can tolerate environment changes. It is used in the manufacture of electrical wires, cables, electrical electrodes, bus bars and legitimate accessories and equipment.
(iii) Gold: It is yellow, ductile, shockproof and highly valuable metal. Its use is negligible in electrical works.
(iv) Aluminum: It is white, ductile, malleable, light, corrosion resistant and of low specific resistance. Due to the abundance available in India, aluminum is used instead of copper, but copper is not used as much for copper as it is used for many electrical works.
(v) Tungsten: It is dark gray, high melting point, tensile and hard metal. It is used to make filaments of electric bulbs and fluorescent tubes.
(vi) Zinc: It is a soft and corrosion resistant metal of blue gray color. It is used for mounting anti-corrosion coating on iron wires, sheets, pipes, ie galvanized. Additionally it is used to make dry cell shells.
(vii) Brass: It is yellow colored, ductile, shockproof, corrosion resistant and strong metal made of copper and zinc. It is used in making connectors, screws, shells etc. of electrical equipment. Many types of brass are made, depending on the percentage presence of ingredients in the mixture.
(viii) Nickel: It is white colored and corrosion resistant metal. It is used to make plates of nickel iron accumulator cells and to offer anti-corrosion coating on other metallic objects.
(ix) Iron: It is a strong, inexpensive, accessible, ductile and malleable metal. Although its specific resistance is about 8 times the typical copper resistance, due to its other properties, it is used to make telephone wires, earth wires and bodies of electrical equipment, laminations, etc.
(x) Tin: It is white, extremely soft and corrosion resistant metal. It is used as an alloy with lead to make fuse wire, solder, etc. Additionally, it is used to provide a coating on other metal wires that is resistant to corrosion and environment effects.
(xi) German Silver: It is an alloy made of 60% copper, 15% nickel and 25% zinc. It is a stronger metal than brass and less affected by atmospheric changes. It is used in place of brass in high quality instruments.
(xii) Lead: It is gray colored, soft and heavy metal. Due to its anti-corrosion properties, it is used in mounting anti-corrosion and anti-corrosion protective coverings on underground cables and making plates of lead-acid accumulators. Additionally, it is used as an alloy with tin to make fuse wire and solder.
(xiii) Mangnin - It is used in making resistor. It is an alloy made of 84% copper, 12% manganese and 4% nickel.
(xiv) Eureka: It is an alloy made of 40% nickel and 60% copper. It is a metal with tensile and high specific resistance. It is used in making high heat resistant resistors, regulators etc.
(xv) Platinum: It is a hard and precious metal like silver. It is used to create contact points.
(xvi) Mercury: It is a metal in liquid state at normal temperature. It is used in thermometers and mercury vapor lamp as mercury vapor.
(xvii) Nichrome: It is a high specific resistance alloy made of 80% nickel and 20% chromium. It is ductile, strong and of high melting point. It is used to make heating elements of electric press, kettle, toaster etc.
(xvii) Carbon: It is non-metallic and has a very high resistance value. It is used in making brushes of resistive and DC machines.