More recently, the federal government has passed legislation, created regulations, and judicated court cases regarding the use and consumption of selenium. It is a non-metallic toxic element related to sulfur and tellurium. It is rarely found in its pure state, combining instead with both metals and non-metals to form organic and inorganic compounds. Unevenly dispersed in the earth's soil, it is primarily found in sedimentary rock in drier regions of the world including vast sections of western North America. Selenium was at first valued for its commercial uses.
Selenium is both photovoltaic and photoconductive.
The former refers to its ability to convert light into electricity. The later deals with its ability to decrease electrical resistance by increasing light exposure. Thus, among other uses, selenium is utilized in the production of photocells, exposure meters, and solar cells. Since it can convert alternating current into direct current it is also used in rectifiers. It is a semiconductor and, as such, is used in many electronic devices.