pulse-duration control
61Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …
62Oscilloscope — This article is about current oscilloscopes, providing general information. For history of oscilloscopes, see Oscilloscope history. For detailed information about various types of oscilloscopes, see Oscilloscope types. Illustration showing the… …
63Boeing E-4 — E 4B in flight Role …
64Jet pack — For other meanings see Jetpack (disambiguation). : The Martin Jetpack, despite its name, has no jets or rockets, but is a small helicopter, and is discussed as such. Jet pack, rocket belt, rocket pack, and similar names, are various types of… …
65Avalanche transistor — An Avalanche Transistor is a bipolar junction transistor designed for operation in the region of its collector current/collector to emitter voltage characteristics beyond the collector to emitter breakdown voltage, called avalanche breakdown… …
66Atmospheric reentry — refers to the movement of human made or natural objects as they enter the atmosphere of a planet from outer space, in the case of Earth from an altitude above the edge of space. This article primarily addresses the process of controlled reentry… …
67Types of radio emissions — The International Telecommunication Union uses an internationally agreed system for classifying radio frequency signals. Each type of radio emission is classified according to its bandwidth, method of modulation, nature of the modulating signal,… …
68Transformer types — Circuit symbols Transformer with two windings and iron core. Step down or step up transformer. The symbol shows which winding has more turns, but not usually the …
69Highgate Wood Telephone Exchange — Highgate Wood is a suburb in North London that was chosen as the site of a trial for an electronic telephone exchange built by members from Joint Electronic Research Council (JERC), which was formed in 1956 and consisted of the British Post… …
70Physical Sciences — ▪ 2009 Introduction Scientists discovered a new family of superconducting materials and obtained unique images of individual hydrogen atoms and of a multiple exoplanet system. Europe completed the Large Hadron Collider, and China and India took… …
