Those materials which do not allow electrons to flow from within, are good conductors of electricity. According to electronic theory, such substances whose atoms do not have free electrons in their outer paths are called good insulator of electricity. The last cell of their atoms always has four electrons. Power has good malicious rubber, asbestos, asbestos, asbestos, porcelain, PVC, Empire cloth etc.
They are not the drivers of electricity. In this, the connective band is full and the driver band is empty.
In these types of materials, the forbidden energy interval between the conductive band and the connective band is very high which is equal to about 6ev and an electron cannot absorb so much energy that it can move from the connective band to the conduction band.
Properties of Good Insulator -
The main features of good conductors are as follows:
1. Specific resistance-
A good conductor specific resistance should be greater than 1012 Ohms.
2. Moisture-inducing materials should not be affected by moisture or water.
3. Permittivity - It is the ratio of capacitance of a capacitor when its plates have been driven by an insulating material and air.
4. Dielectric strength - It is used to convey in insulator. The maximum strength is the maximum kilo volt per millimeter or volt per mill that any substance can keep inside without breaking it.
5. Mechanical power - The mechanical power of a good conductor should be good so that the weather does not affect it.
6. Temperature- The capacity of heat conductors of conductors should be high.
Types of Insulator-
The following is the description of different types of malicious.
1. Mica - It is a good conductor of electricity. Its transitive power is very high. There is little effect of moisture and fire on it. It is a mineral substance. It starts softening at around 600 degrees Centigrade. It is used in electrical products, commutator segment, middle and condensers etc.
2. Rubber - 5% sulfur, zinc oxide and red colored lead are added to make the rubber hard. The rubber thus prepared is called VIR. With this, battery containers, rubber gloves etc. are made.
3. Asbestos - It is used in making sheets, it is used in the arc chamber of electrical press, oven, electric kettle and circuit breaker. It is a mineral substance, on which acid is not affected.
4. Bakelite - It is a good conductor of electricity. It is a special type of plastic material. It is used in preparing materials for switch holders, terminal boards, sockets, electrical wiring fittings, etc. It is heated and molded into the mold to give it the required form. In this way it takes the form of hard matter.
5. Ebonite - It is prepared by mixing 30 to 50 percent of sulfur in rubber. It is prepared after heating at 150 degree centigrade. Its color is black. It is used in making containers of batteries, terminal plates and covers of machines.
6.PVC (P.V.C) - It is a synthetic chemical substance. Its full name is polyvinyl chloride. The effect of moisture and acid on it is less. It is a good conductor of electricity. With this, P.V.C. Wires and cables are made.
7. Glass - This is a good transparent conductor. It does not have the effect of alkali, acid, moisture, oil, grease etc. Bulbs, mercury arc lamps etc. are made by this. It is an early breakdown material. Its mechanical strength is low.
8. Leatheroid Paper - This is a paper of good quality. Its color is green and has some blackness. It comes in the misconduct of E class. It is used for insulating slots in motor windings.
9. Porcelain - It is a very good conductor of electricity. It is a substance made from sugar soil. Pin, shackle, disc insulator mounted on the over head lines are made by this. Kit Kate Fuses are mainly made of porcelain. The basis of the switch is made from this.
10. Prespain Paper - These are good polypropylene, high gloss and pressed paper. They are found in yellow color.