subject: Good Conductors Of Electricity [print this page] Conductors are materials that allow an electric current to flow through them easily. Most metals are good conductors of electricity.
Most metals are good conductors of electricity because, When metal atoms combine with each other, the outermost electrons lose contact with their parent atoms. The remaining positively charged atomic centers form an ordered structure while the outer electrons move freely around the whole sample. These freely moving electrons, called conduction electrons, can carry heat energy and electric charge easily throughout the metal, making metals good conductors of heat and electricity.
A good conductor of electricity is a material which contains movable electric charges. In metallic conductors, such as copper or aluminum, the movable charged particles are electrons. Positive charges may also be mobile in the form of atoms in a lattice that are missing electrons (known as holes), or in the form of ions, such as in the electrolyte of a battery. Non-conducting materials(like glass and Mica) lack mobile charges, and so resist the flow of electric current, generating heat. In fact, all non-conducting(Insulator) materials offer some resistance and warm up when a current flows.
A good conductors of electricity should provide little resistance to the flow of an electric current. Thus, proper design of a good electrical conductor takes into account the temperature that the conductor needs to be able to endure without damage, as well as the quantity of electrical current or electrical conductivity. A good conductor of electricity, such as silver or copper, may have a conductivity a billion or more times as great as the conductivity of a good insulator, such as glass or mica.
The conductors on the basis of rate of flow of charges and their resistance bearing capacity can be divided into superconductors, semiconductors, bad conductors( insulators) and good conductors( at room temperature). All good conductors of electricity contain electric charges which will move when an electric potential difference (measured in volts,V) is applied across separate points on the material. This flow of charge (measured in amperes, I) is what is meant by electric current(I).
The relationship between current, voltage, and resistance in any conductor is given by Ohms law. This law states that the amount of current passing through a conductor is directly proportional to the voltage across the conductor and inversely proportional to the resistance of the conductor. Ohms law can be expressed as an equation, V = IR, where V is the difference in volts between two locations (called the potential difference), I is the amount of current in amperes that is flowing between these two points, and R is the resistance in ohms of the conductor between the two locations of interest.
Some Good Conductors of Electricity:
Most familiar and affordable conductors are metallic. Copper is the most common and also very important material used for electrical wiring. Silver is the best conductor known, but is expensive. Gold(rarely) is used for high-quality surface-to-surface contacts.There are also many Non-metallic conductors, including graphite, all plasmas and solutions of salts.
Conductor materials:
1. Most commonly used metal is copper, copper has a high conductivity.
2. Silver is more conductive than copper , but due to cost it is not practical in most cases except some specialized equipment such as satellite .
3. Aluminium has been used as a good conductor of electricity in housing applications for cost reasons. Aluminium is actually more conductive(and cheaper too) than copper when compared by unit weight, but it has technical problems that have lead to problems when used for household and similar wiring.
4. Gold is used basically for high-quality surface-to-surface contacts(due to it's expensiveness).
5. Nickel, Nickel Chromium alloy, Fe-Cr-Al alloy, Steel Wire, Titanium, Molybdenum are also good conductors of electricity.
Why Metals are Good Conductors of Electricity:
Metals are elements or substances which have one, two or three electrons in their valence shells.The atoms in metals are arranged in a pattern of regular lattice structure called metallic bonding. This type of metallic bonding is due to the electromagnetic interaction between delocalised electrons in lattice. The electrons(valence or free ) are therefore free to move around the lattice of positively charged ions as a "sea of electrons".
Metals are good conductors because the electrons are mobile charge carriers and so can carry the electrical charge through the metal, making it a good conductors of electricity.
All conductors contain electrical charges, which will move when an electric potential difference (measured in volts) is applied across separate points on the material. This flow of charge (measured in amperes) is what is meant by electric current. In most materials, the direct current is proportional to the voltage (as determined by Ohm's law), provided the temperature remains constant and the material remains in the same shape and state.
Most familiar conductors are metallic. Copper is the most common material used for electrical wiring (see main article: Copper wire and cable). Silver is the best conductor, but it is expensive. Because gold does not corrode, it is used for high-quality surface-to-surface contacts. However, there are also many non-metallic conductors, including graphite, solutions of salts, and all plasmas. There are even conductive polymers. (See electrical conduction for more information on the physical mechanism for charge flow in materials).
All non-superconducting materials offer some resistance and warm up during electric currents. Proper design of an electrical conductor takes into account the temperature of the conductor as well as the value of electric current. The motion of charges creates an electromagnetic field around the conductor that exerts a mechanical radial squeezing force on the conductor. The current carrying capacity of a conductor is limited by its ability to dissipate heat. This effect is especially critical in printed circuits, where conductors are relatively small and close together, and inside an enclosure: the heat produced can melt the tracks.
Thermal and electrical conductivity often go together. For instance the sea of electrons causes most metals to act both as electrical and thermal conductors. However, some non-metallic materials are practical electrical conductors without being good thermal conductors.[citation needed]
