Photovoltaic Cells

Such effect, truly fascinating, is identified in the conversion of a type of energy in an other. That is in the transformation of the light in electric power. Analogous to how much characterized from Alexander Time through the thermal effect, for which, heating the splice of two metals of various nature, on it finishes them free of these came to generate a potential difference them, with the obvious result of one mutation of energy from thermal to electrical worker.
Also the photovoltaic effect takes advantage of one splice, that one of two semiconductors, of which one of type N, the other of P type. That it is then the same splice used in the realization of the diode valves, of the transistors and of the integrated circuits and that, in hit coming from the light, it gives origin to a potential difference them, that it is proportional them to the photon number that catches up the zone in which the two superficial ones of the semiconductors they are combined and that it comes called "depletion region".
Practically, all the bipolar diode valves and transistors, equip you of two splices and that they can be it imagines to you as two diode valves connect to you. in "antiseries". when they are you invest yourself from the light can generate the photovoltaic tension. Therefore, in fact, in order to prevent that the light can catch up the splices and alter the correct operation of the semiconductors, the industry supplies to insert them in opaque guards, absolutely inaccessible to the artificial or natural light that is.
Today, the physical process has been wide characterized and taken advantage of in numerous, modern electronic applications and us account can become some, experimenting the phenomenon with a diode valve to the germanium or led in the way suggested in figure 1.

Fig. 1 - Whichever diode valve to the germanium or led, provided that realized in container of transparent material, when it comes hit from the light promotes the photovoltaic effect, that weakest current starts one, of the order of some microampere, in the circuit closed through a tester commutato in the amperometrica function and the scale of the lower values.

Even if the produced energy is minimal and the marked current from the instrument is paltry, of the order of some microampere. But if the tension generated from the splice is weak person, that is from attributing itself mainly to ridottissima the area of this, whose function is various from that one of the promotion of the photovoltaic effect. However, when a splice comes purposely constructed for a wide exposure to the light, then the tension can catch up the value of 0,5 V and also 0,9 V, to second of the component materials and the superficial extension, than measure in square centimeters. Therefore, in the respect of these conditions, the industry has produced and produces of the elements, calls photovoltaic cells exactly to you , from which amounts of sufficient electric power can be derived to feeding small apparatuses electronic electrical workers and. If then these members come opportunely then connect in great number between they, as it will come more ahead said, the tensions to you and the currents come considerable exalted, to the point of feeding edge equipment and furniture motors average, on floating, motors vehicle, satellites space them and spaceships (figure 2).