WHAT IS PHOTOVOLTAICS ?
V. Ryan © 2005
Photovoltaic cells look similar to solar panels but they work in a different way. Solar panels are use to produce hot water or even steam. Photovoltaic panels c**vert the sunlight directly into electricity. A typical example of a device powered by photovoltaic cells is a solar powered calculator. This type of device **ly needs a small amount of electrical power to work and can even be used in a room with artificial light (bulbs / fluorescent light).
Although we see photovoltaic cells powering small devices such as calculators they have a **** practical applicati** especially in the third world. Photovoltaic cells have been developed that will provide electrical power to pump drinking water from wells in remote villages. British Telecom have developed a system that can be used to power a radio teleph**e system. During the day the cells power the ph**e and also charge batteries. The batteries power the ph**e during the night. Often photovoltaic cells are used as a backup to c**venti**al energy. If c**venti**al fails the cells are used to produce electricity.
A TYPICAL PHOTOVOLTAIC CELL Silic** is a material known as a ‘semic**ductor’ as it c**ducts electricity and it is the main material for photovoltaic cells. Impurities such as bor** or phosphorus are added to this base material. These impurities create the envir**ment for electr**s to be freed when sunlight hits the photovoltaic panel. The freeing of electr**s leads to the producti** of electricity.
The diagram above shows a basic photovoltaic cell. The blue represents the main material, silic**. The black round and irregular shapes represent the impurities of bor** or phosphorous. As the sun/light strikes the cell the impurities free up electr**s which ‘bounce’ around at incredible speeds. This creates an electrical charge.
AN ARRANGEMENT OF PHOTOVOLTAIC PANELS - ARIZ**A (USA)
QUESTI**S:
1. Make a list of devices that are powered by photovoltaic cells.
2. Describe devices that you think could be powered by photovoltaic cells (fully powered or as a backup to the electricity power grid).