Coronal seismology — is a technique of studying the plasma of the Sun s corona with the use of magnetohydrodynamic (MHD) waves and oscillations. Magnetohydrodynamics studies the dynamics of electrically conducting fluids in this case the fluid is the coronal plasma.… … Wikipedia
Vacuum tube — This article is about the electronic device. For experiments in an evacuated pipe, see free fall. For the transport system, see pneumatic tube. Modern vacuum tubes, mostly miniature style In electronics, a vacuum tube, electron tube (in North… … Wikipedia
Tetrode — A tetrode is an electronic device having four active electrodes. The term most commonly applies to a two grid vacuum tube. It has the three electrodes of a triode and an additional screen grid which significantly changes its behaviour. Grids The… … Wikipedia
Nor'easter — Satellite image of the intense nor easter responsible for the North American blizzard of 2006. Note the hurricane like eye at the center. A nor easter (also northeaster; see below) is a type of macro scale storm along the East Coast of the United … Wikipedia
Valve audio amplifier - technical — Circuitry and performance Characteristics of valves Valves are very high input impedance (near infinite in most circuits) and high output impedance devices. They are also high voltage / low current devices.While valves themselves are described… … Wikipedia
Pentagrid converter — For other types of frequency converters please, see Frequency converter. The pentagrid converter is a radio receiving valve (vacuum tube) with five grids used as the frequency mixer stage of a superheterodyne radio receiver. Grids of a 12SA7GT… … Wikipedia
wave — I (New American Roget s College Thesaurus) v. wag, shake, sway, flutter, stream (in the wind); signal, motion, gesture, indication; roll, undulate; ripple, swell, billow, flood, surge; flaunt, flourish. n. sea, tide, water, ripple, billow, etc.,… … English dictionary for students
wave — 1. verb 1) he waved his flag in triumph Syn: brandish, shake, swish, move to and fro, move up and down, wag, sweep, swing, flourish, wield; flick, flutter 2) the grass waved in the breeze Syn … Thesaurus of popular words
