noise measuring apparatus
61Rock — /rok/, n. a male given name. * * * I In geology, a naturally occurring and coherent aggregate of minerals. The three major classes of rock igneous, sedimentary, and metamorphic are based on the processes that formed them. These three classes are… …
62Protective relay — See also: Power system protection In electrical engineering, a protective relay is a complex electromechanical apparatus, often with more than one coil, designed to calculate operating conditions on an electrical circuit and trip circuit breakers …
63Triple correlation — The triple correlation of an ordinary function on the real line is the integral of theproduct of that function with two independently shifted copies of itself: int { infty}^{infty} f^{*}(x) f(x+s 1) f(x+s 2) dxThe Fourier transform of triple… …
64Hall effect — For the Colombian band, see The Hall Effect (band). The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular …
65Light-emitting diode — LED redirects here. For other uses, see LED (disambiguation). Light emitting diode Red, pure green and blue LEDs of the 5mm diffused type Type Passive, optoelectronic Working principle Electr …
66Microwave — This article is about the electromagnetic wave. For the cooking appliance, see Microwave oven. For other uses, see Microwaves (disambiguation). A microwave telecommunications tower on Wrights Hill in Wellington, New Zealand Microwaves, a subset… …
67Oxygen — This article is about the chemical element and its most stable form, O2 or dioxygen. For other forms of this element, see Allotropes of oxygen. For other uses, see Oxygen (disambiguation). nitrogen ← oxygen → fluorine ↑ O ↓ …
68Near and far field — This article is about the electromagnetic concept. For the mathematical, see Near field (mathematics). Antenna field regions for antennas that are shorter than the wavelength of the radiation they emit, such as the whip antenna of a citizen s… …
69List of IEC standards — In order to distinguish standards published by the International Electrotechnical Commission numerically from other international standards, their number range was shifted in 1997 by adding 60000. So what used to be called IEC 27 is now… …
70Defence Research and Development Organisation — Sanskrit: बलस्य मूलं विज्ञानम् Strength s Origin is in Science [1] Agency overvi …
