Commercial solar cell spins propeller using halogen light source.

Commercial solar cell spins propeller using small arc lamp. Several types of solar cells (silicon cells, iron-selenium cells) are available for display. Photovoltaic cells convert incandescent light or sunlight directly into electrical energy. They can be hooked up to a projection galvanometer to illustrate voltage or current characteristics. There are several demonstrations that have motor-driven propellers powered by silicon solar cells. Perhaps the helicopter is the most visible in a large class. NOTE: There are many light sources that can be used to drive the motors. Some people prefer carbon arcs (very intense light), while others prefer smaller electric lamps or flashlights. For a greater effect, the light source can be placed about ten feet away from the solar-driven motor. Consult with the demonstration staff.