The various high resistivity materials (including alloys) are described below: 1. Tungsten: (i) Hard metal. (ii) Resistivity twice that of aluminium. (iii) Can be drawn into very thin wires (for making filaments). The thinner the tungsten wire, the greater is its tensile strength. (iv) In the atmosphere or inert gas (Nitrogen, Argon etc.) or in vacuum, tungsten can be readily [...]
Here is a list of popular electrical materials. 1. Materials of Low Resistivity and High Conductivity: These materials should have the least possible electrical conductivity. They are employed for making conductors for all kinds of windings required in electrical machines, apparatus and devices, as well as for transmission and distribution of electrical energy. Requirements of Materials of High Conductivity: The [...]
An important fundamental factor on the basis of which selection of electrical engineering materials is made consists of its physical, chemical, mechanical and electrical properties. Considering this factor alone is an over simplification of the problem involved in selecting a material. There are other factors also which must be considered in order to select the most appropriate material and they [...]
In this article we will discuss about the relationship between structure and property of electrical engineering materials. It is customary to say that every known type of material must be considered for use by the engineer. Admittedly, some materials are not used widely because of poor availability, initial properties, service performance or high cost. Others, such as iron, steel, paper, [...]
Here is a list of commercially available electrical contact materials having application in electrical engineering. 1. Copper: Because of low cost, high electrical and thermal conductivities, it is generally used as contact material. Its drawbacks are poor resistance to oxidation and easy formation of chemical compounds (e.g., sulphides). Its typical applications are control relays, motor starter switches, tap changers. 2. [...]
In this article we will discuss about the applications of low and high resistivity materials in electrical engineering. Applications of Low Resistivity Materials: i. Copper: It is most widely used metal because soft its high conductivity (i.e., low resistivity), Silver has the lowest resistivity but due to its high cost it is not used as conducting material. Copper is available [...]
Here is a list of eleven commonly used electrical engineering materials. 1. Dielectric Materials: Dielectrics do not possess free electric charges and hence do not conduct electric current, this means that the dielectric materials are usually insulating materials which possess a very low electrical conductivity. However while the function of an insulating materials is to obstruct the flow of current, [...]
In this article we will discuss about the energy band concept of conductor, insulator and semiconductor. In an atom, the electrons try to occupy the inner orbit (having minimum energy) but according to Pauli's exclusion principle not more than two electrons can exist in the one energy state. The electrons start occupying the energy states having low energy. Therefore, in [...]
The mathematically perfect crystal is an exceedingly useful concept. In actual crystals, however, imperfections or defects are always present and their nature and effects are often very important in understanding the properties of crystals. This is because some properties of materials such as stiffness, density and electrical conductivity which are termed structure-insensitive, are not affected much by the presence of [...]
When a metal is deformed significantly, the grains become elongated and metal are in a non-equilibrium state. Now when the metal is heated to a temperature of about 0.3-0.5 Tm, Tm being melting temperature of metal, and held at this temperature. The metal attempts to approach equilibrium through a series of interesting processes, namely: (i) Recovery, (ii) Recrystallization and (iii) [...]