The lumen (symbol: lm) is the unit of the International System of Units to measure the luminous flux, a measure of the light power emitted by the source. The luminous flux of radiant flux difference that the former provides the variable sensitivity of the eye to different wavelengths of light and the latter involves all electromagnetic radiation emitted by the source according Wien law and Stefan-Boltzmann regardless of whether such radiation is visible or not. 1 lm = 1 cd. sr = 1 lx. m2

Photovoltaic energy is produced by solar radiation using devices called photovoltaic cells. It is ideal for supplying all kinds of isolated houses, shelters, but also can be used to supply electricity on a large scale. We show the operating principle "In a semiconductor exposed to light, a photon of energy starts an electron, creating both a" gap "in the atom excitador. Normally, the electron quickly finds another hole to refill it, and the energy provided by the photon thus dissipates as heat. The principle of a photovoltaic cell is to force the electrons and holes to move towards the opposite side of the material rather than simply recombine in it: thus, there will be a potential difference and thus tension between the two sides of the material,as in a stack "The first ground application of a commercial installation of photovoltaic cell was developed in Japan in 1966. In the picture: 1 - PV Modules 2 - Regulation and Control 3 - Battery 4 - Inverter to power.... 220V