PHOTOVOLTAIC+CELLS+-+Yvonne

= ﻿**__Photovoltaic Cells__** =

The word 'photovoltaic' means the transfer of energy from the sun and later converted into electrical energy.
The Greek term "photovoltaic" means "light". The Italian term "voltaic", means electricity, derived from the name of physicist Volta. == Photovoltaic is the process of using the radiation from the sun and converting the energy to DC electrical energy. It uses semi electrical conductors with the *photovoltaic effect'. Photovoltaic generates power with solar panels and this forms a number of 'cells' containing different photovoltaic materials. Currently, the materials used for photovoltaic cells range from monocrystalline silicon to copper indium selenide (or sulphide). The demand for renewable energy sources and this meant that many photovoltaic arrays have improved. ==

[[image:800px-Nellis_AFB_Solar_panels.jpg width="448" height="282"]]
(image above shows one of the largest photovoltaic solar power plant in the US known as the Nellis solar power plant, a larger plant was invested in recently.)

The Nellis Solar Power Plant
=It is located in Clark County, Nevada, towards the northeast of Las Vegas. It can generate up to 25 million kW-h each year and supply more than 25% of the power used at the Air Force Base. The power plant takes up 0.57 km2and has an advanced sun tracking system, containing roughly 70,000 solar panels. The power plant produces about 20% of its peak power generation capacity of about 13MW AC. = = = Photovoltaics use solar cells to convert energy from the sun to electrical energy. *The 'Photovoltaic effect' idicates to the photons of light colliding with electrons and hitting them into "a higher state of energy" and thus creating energy. Solar cells produce DC converted from the energy from the sun and this can be used to recharge electronics, etc. The first kind of photovoltaic was used to power spacecrafts like the orbiting satellite. Solar cells are usually protected by bering very tightly enclosed behind a glass. If more energy was needed than one solar cell, the cells can connect together electrically to form **solar panels.**
 * Energy transfers: **
 * Solar cells - **

(a solar cell) **__What is the meaning of the photovoltaic effect?__**  The photovoltaic effect was first discovered by physicist A. E. Becquerel from France in 1839. However, the first solar cell was built in 1833 by a man called Charles Fritts. Russian physicist Aleksandr Stoletov built the first photoelectric cell in 1888. Albert Einstein’s 1905 explanation of the photoelectric effect was awarded a Nobel Prize in Physics in 1921.  ﻿ A detailed method of how photovoltaic effect will take place in solar or photovoltaic cells:  ﻿  Photons in the sunlight collide with the solar panel and gets absorbed by semiconducting materials, such as monocrystalline silicon. Electrons are therefore loose from their atoms due to the collision, allowing them to flow through the material to produce electricity. Electrons can only move in one direction. Solar cells convert solar energy into a useful amount of DC electricity.   "Many current solar cells are cut into wafers between 180 to 240 micrometers thick that are then processed like other semiconductors." -http://en.wikipedia.org/wiki/Solar_cell 