The effectiveness of a solar cell is determined by the percentage of sunlight that it transforms into electricity. To evaluate a photovoltaic device, a solar simulator passes an applied voltage across the solar cell and the current produced is recorded. The graphical result is a current-voltage curve, with the current of the solar cell plotted against the voltage that was applied. The curve can then be used to determine the cell or panels’ power conversion efficiency.
The solar cell testing equipment is often made specifically for a particular type of panel or cell, such as thin film and high-efficiency designs.