Sunday, March 4, 2012

Conductive and insulating materials

Materials They can be classified in conductors or insulators, according to leading electricity with ease or not do so. This classification depends on how strongly are United electrons to its structures, as this is an indication of the energy required to give them mobility inside the material, i.e. to conduct electricity.

This differentiation is useful within certain limits. For example, quartz
melt is 10 quadrillion times better insulation than copper, which is why both tend to be regarded as excellent insulator and conductor, respectively. Metals and non-distilled water are considered to be good drivers, plastics and glass are good insulators.

Water in its chemically pure State is an insulating substance. However, in nature are found in solution with other substances that occur in its structure ions with relative freedom of movement. In such circumstances, these solutions are very good conductive of electricity.

A strategy used to avoid accidents caused by the accumulation of static electricity is to increase the surface conductivity
by elevation of relative humidity. Many times it is installed
for this purpose an integrated team humidification system
air conditioning. The moist air conducts electricity and prevents the surfaces are loaded.

This classification are currently added materials called semiconductors such as Silicon and germanium, which are good insulators when they are in pure crystalline state, but they conduct electricity when only some atoms of the Crystal are replaced with others, such as arsenic or boron, using the technique known as taken drugs of the material.

Semiconductors have extensive technological application, for example in the manufacture of transistors.

Some materials that are considered good drivers increase their conductivity virtually infinite when it cools them at temperatures close to absolute zero (- 273 K): are the so-called superconductors.

Currently, found some ceramic materials superconductors at temperatures of more than 100 k. Isabela great expectations with regard to the design of superconducting materials to
higher temperatures that would enable significant energy savings.

In conductive materials, the burden is distributed on the surface, which is easily understandable if one takes into account the repulsion between the equal sign loads and relative mobility available in good conductivity materials.

The concentration of load depends on the curvature of the surface, and can be verified experimentally that the maximum concentration occurs in the értices or tips.

The human body can be considered as a good driver. When the relative humidity is low, you can accumulate loads fairly high, caused for example by the friction of shoes with soil insulation.

The friction of the garments of silk, wool or synthetic fibres, that when withdrawals result in often small sparks electric also audible and visible as a weak Crackle can also be observed.

These considerations become significant importance as to avoid accidents for those people who work with highly flammable materials and also for which handled with sensitive electronic equipment, that they might suffer some damage by the action of this small Download.