Solar Cells

Introduction

Energy produced by nuclear reactions on the sun is called solar energy. Solar energy travels to Earth in the form of light. Solar cells, also called photovoltaic (PV) cells, change the light energy to electrical energy that can be used to power devices, such as calculators, cars, homes, or satellites. A solar cell is made of a semiconducting material such as silicon. When light strikes the cell, it provides enough energy to move electrons through the cell producing an electric current. A single solar cell puts out a very small current when struck by light. Wiring large numbers of solar cells together will produce higher currents. The amount of light that falls on the Earth is enormous, but not all light actually reaches the surface. About a third is reflected back into space and some is absorbed by the atmosphere. You can calculate the power produced by a solar cell by measuring its voltage. In this activity, you will use a Differential Voltage Probe to compare the voltages produced by a single solar cell and by two solar cells wired together. Then you will calculate the power output from each cell combination.

Objectives

In this experiment, you will

• Use a Voltage Probe and NXT to measure voltage from a solar cell.
• Wire a series circuit.
• Calculate power output.
• Compare multiple solar cells.