These cells are semiconductor junction devices used for converting radiation energy into electrical energy.These cells generate a voltage proportional to electromagnetic radiation intensity a voltage proportional to electromagnetic radiation intensity and are called the photovoltaic cells because of their voltage generating capability.An example of such a cell is a silicon solar cell,which converts radiant energy of the sun into electrical energy.
Selenium and silicon are the most widely used materials for solar cells,though gallium arsenide,indium arsenide and cadmium sulphide are also used.
The construction and cross section of a typical power solar cell for use as an energy converter are given in fig. the surface layer of P-type material is extremely thin so that light can penetrate to the juntion. The nickel-plated ring around the P-type material is the positive output terminal,and the plating at the bottom of the N-type material is the negative output terminal.power solar cells are also available in flat strip form for efficient coverage of available surface areas.The circuit symbol often used for a photovoltaic cell shown in fig.
The photovoltaic cell can be operated satisfactorily over a wide range of temperature(say from -100 to 125 degree C). the temperature variations have little effect on short-circuit current but affect the open-circuit output voltage considerably.These variation may be of the order of a few mV per degree C in output voltage. An individual solar cell generates an open-circuit voltage of about 500mV (depending on light intensity) when active. However, photocells can be connected in series to increase the available terminal voltage.
The advantage of such devices are their extremely fast response i.e., these devices can be used as energy convertors directly.
Multiple-unit silicon photovoltaic devices may be used for sensing light in application such as reading punched cards in the data processing industry.
Gold-doped germinium cells with controlled spectral response characteristic act as photovoltaic device in the infrared region of the spectral and may be used as infrared detectors.
solar cells are extensively used as a source of power for many space satellites.The array of junctions can be distributed over the surface of the satellite or can be contained in solar cell "paddles" attached to the main body of the satellite. Application of solar cells are not restricted to outer space.It is possible to have useful power from the sun in terrestrial application using solar cells, even though the solar intensity is reduced by the atmosphere. About kW/m2 is available in a particularly sunny location but not all of this solar power can be converted into electrical power.
Selenium and silicon are the most widely used materials for solar cells,though gallium arsenide,indium arsenide and cadmium sulphide are also used.
The construction and cross section of a typical power solar cell for use as an energy converter are given in fig. the surface layer of P-type material is extremely thin so that light can penetrate to the juntion. The nickel-plated ring around the P-type material is the positive output terminal,and the plating at the bottom of the N-type material is the negative output terminal.power solar cells are also available in flat strip form for efficient coverage of available surface areas.The circuit symbol often used for a photovoltaic cell shown in fig.
The photovoltaic cell can be operated satisfactorily over a wide range of temperature(say from -100 to 125 degree C). the temperature variations have little effect on short-circuit current but affect the open-circuit output voltage considerably.These variation may be of the order of a few mV per degree C in output voltage. An individual solar cell generates an open-circuit voltage of about 500mV (depending on light intensity) when active. However, photocells can be connected in series to increase the available terminal voltage.
The advantage of such devices are their extremely fast response i.e., these devices can be used as energy convertors directly.
Multiple-unit silicon photovoltaic devices may be used for sensing light in application such as reading punched cards in the data processing industry.
Gold-doped germinium cells with controlled spectral response characteristic act as photovoltaic device in the infrared region of the spectral and may be used as infrared detectors.
solar cells are extensively used as a source of power for many space satellites.The array of junctions can be distributed over the surface of the satellite or can be contained in solar cell "paddles" attached to the main body of the satellite. Application of solar cells are not restricted to outer space.It is possible to have useful power from the sun in terrestrial application using solar cells, even though the solar intensity is reduced by the atmosphere. About kW/m2 is available in a particularly sunny location but not all of this solar power can be converted into electrical power.
No comments:
Post a Comment