The plasma chambers suspend the silicon and the phosphorus or boron molecules in a gaseous state. This mixture is pushed into a chamber which has electrodes at the top and bottom. When the electrodes are charged an electric field is produced between them. The electric field removes some of the electrons from the mixture so creating a gas of positively charged ions, a plasma. A stainless steel or glass sheet with an indium/tin oxide layer is passed into the chamber and between the electrodes. The plasma-like gas deposits charged particles on to the uncharged surface of the steel or glass substrate. Depending upon the chemical nature of the gaseous mixture fed into the chamber, one of the three layers which make up the photovoltaic cell will be formed. The thickness of the layers depends on the speed at which the sub state passes through the chamber, and the size of the chamber.
Corona has many advantages and disadvantages. In the correct design of a high voltage overhead line, a balance should be struck between the advantages and disadvantages. ADVANTAGES (i) Due to corona formation, the air surrounding the conductor becomes conducting and hence virtual diameter of the conductor is increased. The increased diameter reduces the electrostatic stresses between the conductors. (ii) Corona reduces the effects of transients produced by surges. DIS-ADVANTAGES (i) Corona is accompanied by a loss of energy. This affects the transmission efficiency of the line. (ii) Ozone is produced by corona and may cause corrosion of the conductor due to chemical action. (iii) The current drawn by the line due to corona is non-sinusoidal and hence non-sinusoidal voltage drop occurs in the line. This may cause inductive interference with neighboring communication lines.
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