Electrotechnics: Basics


Static electricity

With static electricity familiar to almost everyone. Have you ever seen lightning? This is the phenomenon of static electricity enormous power. Static electricity builds up on the surface due to friction of dissimilar materials that are insulators. Are static electricity in daily life? Yes, it applied and it is possible that you have a device in which static electricity is important. This laser printer and copier (Xerox). In addition to laser printers static electricity successfully fights air pollution from dust.

We used to take electricity for granted, it is difficult to imagine that until the end of the 19th century human civilization has existed without electricity. These pioneers of electrical engineering as Alessandro Volta, Michael Faraday, Joseph Henry, Thomas Edison, Nikola Tesla, learned the secrets of power.

lightning strikes

In the early 19th century the only type of electricity that people knew it was static electricity. The ancient Greeks had no idea of ​​the electric charges, but they worked out (accumulated) static electricity by friction of various substances of different nature (amber, hair, etc.) together. They did not think then that you can use electricity for lighting and power machines. One of the people who was able to find a connection between static electricity and electrical shock, the US government has been activist, scientist and inventor Benjamin Franklin.

Benjamin Franklin

Potential and kinetic energy

Static electricity can be represented as the potential energy of the charges and the effect of an electric current as the kinetic energy of motion (changing) charges. This analogy is very appropriate. Electric charge has value and does not change over time, its energy can be characterized by an electric field formed by them and this energy is potential. If the charge will start to change over time, that is, to decrease or increase, then we should talk about the phenomenon of the electric current and the kinetic energy.

What makes static electricity?

Just as the ancient Greeks, we tend to think of static electricity comes from the friction of things. If you live in a house where there is a nylon carpet and metal handles, then you repeatedly observed small static discharges, which causes a small electric shock. When you walk on the carpet, then a static charge that is discharged on the metal door knob. From this you can conclude that the static electricity due to the friction that is similar to the production of heat and fire through friction. But it turns out it is not so!

Triboelectric effect

It is not friction. The bottom line is that we are creating a contact between two different materials. Vigorous rubbing two different things when they are repeatedly brought into contact, leading to the fact that static electricity generated by a phenomenon known as Triboelectricity (or triboelectric effect). All materials are constructed from atoms which have a positive core in the center surrounded by a cloud of electrons. When some atoms have a more powerful attraction than the atoms of other substances, when their mutual approximation, the electrons begin to move toward a stronger atom (matter). This causes a change in the energy state of the electrons and, therefore, the electrons of the atoms of one substance can escape and go to the atom of another substance.

Fur, glass, ebony Experience electrostatics

As a result, the material becomes a new holder of the electrons when the other material loses them. Thus, electric charges generated static electricity. The energetic friction which is to create a contact between two substances, and its rupture, the more possible to accumulate static charge.

If you are experimenting with different materials, it is able to detect that some materials are able to accumulate a positive charge, and the other negative, some materials make it better than others, and some worse. It turns out that we can rank the materials in order of their compliance with the charge that they receive.

Triboelectric series

Triboelectric series

If you rub each other the materials are very close in order of size in the triboelectric series, how long and vigorously rubbed you would not have them, you will not be able to receive static electricity at all, or it will be very small. This proves that the cause of the generation of static electricity is no friction, and the triboelectric effect. Of paramount importance is the substance of materials properties of the atoms involved in friction and friction is very attached conditions.

Date: 01.28.2016

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© Valentin Grigoryev


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