Russell Ohl is generally recognized for patenting the modern solar cell (US2402662, "Light sensitive device"). Ohl was a notable semiconductor researcher prior to the invention of the transistor. A patent is a set of exclusive rights granted by a government to an inventor or applicant for a limited amount of time (normally maximum 20 years from the filing date, depending on extension). ... A solar cell, or photovoltaic cell, is a semiconductor device consisting of a large-area p-n junction diode, which, in the presence of sunlight is capable of generating usable electrical energy. ... A semiconductor is a material that is an insulator at very low temperature, but which has a sizable electrical conductivity at room temperature. ... Through hole transistors (tape measure marked in centimeters) The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilisation, signal modulation and many other functions. ...

Russell Ohl’s specialized area of research was into the behavior of certain types of crystals. He worked on materials research in the 1930’s at AT&T's Bell Labs’ Holmdel facility, investigating diode detectors suitable for high-frequency wireless, broadcasting, and military radar. His work was only understood by a handful of scientists in the organization, one of whom was Dr. Walter Brattain (one of the trio who invented the germanium bipolar transistor in 1947, and who would be awarded the Nobel Prize for Physics in 1956). Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... AT&T (formerly an abbreviation for American Telephone and Telegraph) Corporation (NYSE: T) is an American telecommunications company. ... Bell Telephone Laboratories or Bell Labs was originally the research and development arm of the United States Bell System, and was the premier corporate facility of its type, developing a range of revolutionary technologies from telephone switches to specialized coverings for telephone cables, to the transistor. ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Wireless is an old-fashioned term for a radio receiver, referring to its use as a wireless telegraph. ... Note: broadcasting is also the old term for hand sowing. ... This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ... Walter Houser Brattain (February 10, 1902 – October 13, 1987) was a physicist who, along with John Bardeen, invented the transistor. ... List of Nobel Prize laureates in Physics from 1901 to the present day. ...

Ohl, in 1939, discovered the PN barrier (or as it became known - the “PN junction”). At the time hardly anyone knew anything about the impurities within these crystals, but Russell Ohl discovered the mechanism by which it worked. It was the impurities which made some sections more resistant to electrical flow than others, and thus it was the "barrier" between these areas of different purity that made the crystal work. Ohl later found that super-purifying germanium was the key to making repeatable and usable semiconductor material for diodes. All diodes (incl. LEDs, laser diodes etc) are descendents of Ohl's work. His work with diodes led him later to develop the first selenium solar cells. A semiconductor is a material that is an insulator at very low temperature, but which has a sizable electrical conductivity at room temperature. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... The article on electrical energy is located elsewhere. ... General Name, Symbol, Number germanium, Ge, 32 Series metalloids Group, Period, Block 14 (IVA), 4, p Density, Hardness 5323 kg/m3, 6 Appearance greyish white Atomic properties Atomic weight 72. ... Types of diodes A diode functions as the electronic version of a one-way valve. ...

See also

• Battery
• Solar cell
• Transistor

Four double-A batteries In science and technology, a battery is a device that stores energy and makes it available in an electrical form. ... A solar cell, or photovoltaic cell, is a semiconductor device consisting of a large-area p-n junction diode, which, in the presence of sunlight is capable of generating usable electrical energy. ... Through hole transistors (tape measure marked in centimeters) The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilisation, signal modulation and many other functions. ...

External links

• U.S. Patent 2402662 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=2402662.WKU.&OS=PN/2402662&RS=PN/2402662) -- "Light sensitive device"

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