24-08-2012, 12:01 PM
Electromagnetic Fields & Waves
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Stationary Electric Fields
A field is said to be electric when it contain electrons and ions. Sometimes the change in that field with time may be considered as constant and we can call it stationary electric field.Electrons and ion guns are good examples of electrostatic problems where the distribution of fields is of great importance.Electrode shapes are designed to accelerate particles from a source and focus them into a beam of desired size and velocity.Electron gun is used in cathode-ray oscilloscope,in television and in microwave.
Many electronic circuit elements may have rapidly varying currents and voltage but at any instant the fields can be represented in the form of static field equations.
Transmission lines,millimeter-wave integrated circuits have properties that can be calculated by the laws for static fields.
There are other applications of static electric fields.The electrostatic precipitators used to remove dust and othet solid particles from air ,xerography, and power switches and transmission system also use electrostatic field concept.
But the problem is that how to find the distribution of fields produced by a given source. we normally have to deal with formulas and laws like Coulomb’s law and transform it to other form required to solve particular problems.We also need to improve knowledge in vector algebra to solve complex time-varying problems.