- Galvanometer
- 180 cm of insulated copper wire (90 cm blue and 90 cm red)
- Thin ply aluminium foil
- Portable radio(discarded)
- Electrical tape
- Lacquer thinner
- Cardboard strip
- Soft rag
Elements of the Solar Cell
Solar cells operate by taking the sun’s radiant energy and converting it directly into electric current. The element selenium was the first substance from which these cells were made. The element silicon one of the most abundant element in earth converts a much higher % of suns rays in to electricity .
A solar cell consists of a very thin wafer of silicon over which a delicate meral grid is applied . the grid harvests electrons from silicon without shading it from sun. One cell by itself produces too little power for practical purpose , so many cells are usually connected in a series.
Construction
Although you can buy the cells in electronic stores , a discarded older model portable radio can provide raw materials for the construction of our own cell. The current produced will be very small , but you’ll ger a response from a galvanometer.
Open the radio and remove the selenium rectifier from inside. The rectifier from has a panel of six plates, each with a copper brown selenium wafer soldered at the ends. With a little cleaning and right connections , each plate can function as a cell.
Carefully cur the plates from the rectifier, and remove any paint with lacquer thinner on a soft cloth. Avoid rubbing too vigorously ,you don’t want to scratch the delicate selenium surface.Glue the plates , metal side down to sthe strip of cardboard. Space them evenly.
Cut the red wire unto six 2 inch pieces and the blue wire into six 4 inch pieces. Lay the pieces out in pairs. Cut the thin foil into small squares , just large enough to act as contact pads for the wire tips . Now with a tiny bit of solder connect one end of both red and blue wires to the contact pads , leaving the other ends free.
With small strips of tape, attach the contact pads of the blue wires to the selenium squares. Tape the contact pads of the red wires to the metal bases . Splice the six blue wires to the longer piece of the blue wire for the galvanometer . Splice the six red wires into a larger piece of red wire , functioning as a positive lead wire.
Shine a strong light on the panels . Watch the needle swing as it registers an electric current. With a strong light source and many more cells connected in series , you could even light a 6 volt flash light bulb or power a small motor.