Wednesday, December 9, 2009


How Solar Panels Work and Their Use

Yeiram Martínez

Solar cells are made of two type of semiconductors. N-Type doped silicon, this type can conduct electricity in a much more efficient way than the regular silicon because they are doped with impurities that have extra electrons. These electrons move freely and flow as a current, this works with a second layer called P-Type semiconductors. This layer attracts electrons because they are doped with impurities that are missing one electron. This two layers allow an electric current to flow if an external energy is applied such as light photons.
Solar panels consist of multiple individual solar cells connected either in series or parallel. Each of these solar cell has a voltage of 0.5V and a current from 100-115mA. To make a solar panel around 28-40 cells are connected together and produce a DC electric output of 12V and 4A.
Solar energy is converted to electricity with the photoelectric effect. When the light comes to contact with the atoms in the P-Type semiconductor, the energy in the light photon is absorbed, this excites the atom and causes the excess electron to be ejected from the atom, this causes an electron flow which creates the current of the cell and the force of the electron across the P/N layers, this creates the voltage of the cell.
Solar arrays consist of multiple solar panels, this panels could be use to power up a house, office or any energy consuming structure. Today there is in the market different systems that store the produced DC electricity in batteries, convert this DC Electricity to AC for home use, and synchronize the voltage produced with the voltage in the grid allowing the produced electricity to enter the energy grid. This causes the electric meter to run backwards. The installation of this system is very expensive but at the long run is beneficial for the owner because they don’t consume electricity. The following image presents a diagram of an arrangement of solar panels connected to a system that was previously explained.

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