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n/a Ensembl n/a n/a UniProt n a n/a RefSeq (mRNA) n/a n/a RefSeq (protein) n/a n/a Location (UCSC) n/a n/a PubMed search n/a n/a Wikidata View/Edit Human Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase (EC 2.4.2.1) is an enzyme that in humans is encoded by the NP gene. It catalyzes the chemical reaction purine nucleoside + phosphate ⇌ {\displaystyle \rightleftharpoons ...
In a diode model two diodes are connected back-to-back to make a PNP or NPN bipolar junction transistor (BJT) equivalent. This model is theoretical and qualitative. This model is theoretical and qualitative.
Thus, it is being researched if the quantum mechanical properties can be used for more advanced purposes than simple transistors (e.g. spintronics). Physicists at the University of Arizona, in collaboration with chemists from the University of Madrid, have designed a single-molecule transistor using a ring-shaped molecule similar to benzene.
The diagram shows a schematic representation of an NPN transistor connected to two voltage sources. (The same description applies to a PNP transistor with reversed directions of current flow and applied voltage.) This applied voltage causes the lower p–n junction to become forward biased, allowing a flow of electrons from the emitter into the ...
The connections are illustrated in the adjacent diagram. Because the p-type material is now connected to the negative terminal of the power supply, the ' holes ' in the p-type material are pulled away from the junction, leaving behind charged ions and causing the width of the depletion region to increase.
The junction version known as the bipolar junction transistor (BJT), invented by Shockley in 1948. [10] Later the similar thyristor was proposed by William Shockley in 1950 and developed in 1956 by power engineers at General Electric (GE). The metal–oxide–semiconductor field-effect transistor (MOSFET) was also invented at Bell Labs.
A schematic diagram of the Ebers-Moll models of a PNP BJT. The base, collector and emitter currents are I B, I C and I E, the common-base forward and reverse current gains are α F and α R, and the collector and emitter diode currents are I CD and I ED. Date: 4 August 2010, 05:26 (UTC) Source: Ebers-Moll_Model_PNP.PNG; Author
These transistors have PNP complementary types, with only the second digit changed (to a number normally greater than 4) to indicate the reversed polarity, e.g. a BC177 is PNP version of the BC108, and a BC559 is a PNP version of a BC549.