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Russell Ohl
Russell Shoemaker Ohl (January 30, 1898 – March 20, 1987) was an American scientist who is generally recognized for patenting the modern solar cell (, "Light sensitive device"). Ohl was a notable semiconductor researcher prior to the invention of the transistor. He was also known as R.S. Ohl. Russell Ohl’s specialized area of research was into the behavior of certain types of crystals. He worked on materials research in the 1930s 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). Ohl, in 1939, discovered the PN barrier (or as it became known, the “P–N junction”). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allentown, Pennsylvania
Allentown ( Pennsylvania Dutch: ''Allenschteddel'', ''Allenschtadt'', or ''Ellsdaun'') is a city in Lehigh County, Pennsylvania. The city has a population of 125,845 as of the 2020 census. It is the fastest-growing major city in Pennsylvania and the state's third largest city, behind Philadelphia and Pittsburgh. It is the largest city in both Lehigh County and the Lehigh Valley, which had a population of 861,899 and was the 68th most populous metropolitan area in the U.S. as of 2020. Allentown was founded in 1762 and is the county seat of Lehigh County. Located on the Lehigh River, a tributary of the Delaware River, Allentown is the largest of three adjacent cities, along with Bethlehem and Easton, in Lehigh and Northampton counties that form the Lehigh Valley region of eastern Pennsylvania. Allentown is located north of Philadelphia and west of New York City. History Origins In the early 1700s, the area that is now Allentown and Lehigh County was a wilderness o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lillian Hoddeson
Lillian Hartman Hoddeson (born 20 December 1940, in New York City) is an American historian of science, specializing in the history of physics and technology during the 2nd half of the 20th century. Education and career Hoddeson received in 1957 a high school diploma from the Bronx High School of Science, in 1961 a bachelor's degree in physics from Barnard College, and in 1966 a Ph.D. in physics from Columbia University with a dissertation on solid-state physics. She was an assistant professor of physics from 1967 to 1970 at Barnard College and from 1971 to 1976 at Rutgers University. In 1974–1975 she was a visiting fellow at Princeton University and took Thomas Kuhn's "History of Quantum Mechanics" graduate course. From 1977 to 1992 she held various academic positions at the University of Illinois at Champaign-Urbana, before becoming there an associate professor from 1993 to 2000 and a full professor from 2000 until her retirement. Since 1978 she has held the position of Fermila ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Birth Of The Information Age
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of pronoun ''thee'') when followed by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electrical power, power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more are found embedded in integrated circuits. Austro-Hungarian physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1926, but it was not possible to actually cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cell
A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.Solar Cells chemistryexplained.com It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, , or resistance, vary when exposed to light. Individual solar cell devices are often the electrical building blocks of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (electricity)
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used. Among many uses, diodes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors silicon and tin. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was discovered comparatively late in the discovery of the elements. Germanium ranks near fiftieth in relative abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev predicted its existence and some of its properties from its position on his periodic table, and called the element ekasilicon. In 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkler named the element after his country, Germany. Germanium is mined primarily from sphalerite (the primary ore of zinc), though germani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field. When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistance (electricity)
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ). The resistance of an object depends in large part on the material it is made of. Objects made of electrical insulators like rubber tend to have very high resistance and low conductance, while objects made of electrical conductors like metals tend to have very low resistance and high conductance. This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather than i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Institute Of Physics
The American Institute of Physics (AIP) promotes science and the profession of physics, publishes physics journals, and produces publications for scientific and engineering societies. The AIP is made up of various member societies. Its corporate headquarters are at the American Center for Physics in College Park, Maryland, but the institute also has offices in Melville, New York, and Beijing. Historical overview The AIP was founded in 1931 as a response to lack of funding for the sciences during the Great Depression. /www.aip.org/aip/history "History of AIP" American Institute of Physics. July 2010. It formally incorporated in 1932 consisting of five original "member societies", and a total of four thousand members. A new set of member societies was added beginning in the mid-1960s. As soon as the AIP was established it began publishing scientific journals. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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