This paper discusses photovoltaic panel systems and reviews their electrical properties and use in several industrial fields. We explain how different photovoltaic panels may be characterized by undergraduate students at university using simple methods to retrieve their electrical properties (power, current and voltage) and compare these values with those stated by the manufacturer. We also discuss how the efficiency of solar panels depends upon their construction, temperature, net irradiation and geographic location. (Contains 4 tables and 21 figures.)