I-V SOURCE-MEASURE INSTRUMENTS (I-V Testers)

In principle, solar or photovoltaic (PV) cells convert light energy into useful electrical power. These cells are produced from light-absorbing materials. When the cell is illuminated, optically generated carriers produce an electric current when the cell is connected to a load.

Researchers need to perform a variety of measurements in order to determine the electrical characteristics of PV cells. Characterizing the cells often involves measuring the current and capacitance as a function of an applied DC voltage. The measurements are usually done at different light intensities and temperature conditions. Important device parameters can be extracted from the current-voltage (I-V) and capacitance-voltage (C-V) measurements, such as the conversion efficiency (η), the maximum power point (Pmax), and the fill factor (FF). Electrical characterization is also important to determine losses in the PV cell. Essentially, electrical characterization is needed to determine ways to make the cells as efficient as possible with minimal losses.

A source measure unit (SMU, also called as "source-measurement unit") is used for the electrical characterization of PV cells. A SMU is an electronic instrument that is capable of both sourcing and measuring at the same time. It can precisely force voltage or current and simultaneously measure precise voltage and/or current.

SMU integrates the capabilities of a power supply or function generator, a digital multimeter (DMM) or oscilloscope, a current source, and an electronic load into a single, tightly synchronized instrument.