What is the application of electrostatics

Electrical engineering modules / School / Applications of electrostatics

copier

The imaging drum of a copier is initially charged strongly and evenly via a so-called coronary wire. The areas that should later be white are then discharged by the light of a laser beam. In the next step, toner powder sticks to the roller - and only to the charged areas. The toner is rolled onto the paper and in the last processing step the toner dust is burned into the paper.

Painting

When painting complex workpieces, for example cars, there used to be great difficulties in achieving a uniform color thickness even in depressions and in hard-to-reach places. A little more paint was sprayed, which increased consumption. The layer thickness became uneven. If the paint mist is positively charged and the body is negatively charged, the paint droplets are distributed absolutely evenly. Additional advantage: Very little color is lost in the environment.

Flue gas cleaning

Another tried and tested application is flue gas cleaning in power plants: The smoke is passed through a chamber with many tightly stretched wires. A strong electric field removes dust and soot particles from the exhaust gas.

TV

An electric field is also used in televisions: a filament (cathode) is used to generate free electrons, which are accelerated with a voltage of tens of thousands of volts in the direction of the positively charged anode. The front inside of the picture tube is covered with a fluorescent layer. Where the electrons hit, they create a point of light.

oscilloscope

One uses for the graphic representation of electrical processes Oscilloscopes. The principle is similar to that of a television: an electron gun shoots an electron beam at the fluorescent layer. In the television, the electron beam is aimed at the desired pixel with electromagnets, but magnetic coils are not fast enough for high-frequency changes. This is why an electric field is used to deflect the electron beam horizontally and vertically. The deflection voltages are directed to two pairs of plates.