the state or quality of being ample, esp. as to breadth or width; largeness; greatness of extent.
2.
large or full measure; abundance; copiousness.
3.
mental range, scope, or capacity.
4.
Physics. the absolute value of the maximum displacement from a zero value during one period of an oscillation.
5.
Electricity. the maximum deviation of an alternating current from its average value.
6.
Astronomy. the arc of the horizon measured from the east or west point to the point where a vertical circle through a heavenly body would intersect the horizon.
Astronomy The angular distance along the horizon from true east or west to the intersection of the vertical circle of a celestial body with the horizon.
Physics The maximum absolute value of a periodically varying quantity.
Mathematics
The maximum absolute value of a periodic curve measured along its vertical axis.
The angle made with the positive horizontal axis by the vector representation of a complex number.
Electronics The maximum absolute value reached by a voltage or current waveform.
1549, from L. amplitudinem (nom. amplitudo, gen. amplitudinis) "wide extent, width," from amplus (see ample). Amplitude modulation in ref. to radio wave broadcast (as opposed to frequency modulation) first attested 1921, usually abbreviated a.m.
Physics One half the full extent of a vibration, oscillation, or wave. The amplitude of an ocean wave is the maximum height of the wave crest above the level of calm water, or the maximum depth of the wave trough below the level of calm water. The amplitude of a pendulum swinging through an angle of 90° is 45°. Compare frequency.
Electronics The amount by which a voltage or current changes from zero or an average value.
Main Entry: am·pli·tude Pronunciation: 'am-pl&-"t(y)üd Function: noun 1: the extent or range of a quality, property, process,
or phenomenon: as a: the extent of a vibratory movement (as of a pendulum) measured from the mean position to an extreme b: the maximum departure of the value of an
alternating current or wave from the average value
Am"pli*tude\, n. [L. amplitudo, fr. amplus: cf. F. amplitude. See Ample.]1. State of being ample; extent of surface or space; largeness of dimensions; size. The cathedral of Lincoln . . . is a magnificent structure, proportionable to the amplitude of the diocese. --Fuller. 2. Largeness, in a figurative sense; breadth; abundance; fullness. (a) Of extent of capacity or intellectual powers. "Amplitude of mind." --Milton. "Amplitude of comprehension." --Macaulay. (b) Of extent of means or resources. "Amplitude of reward." --Bacon. 3. (Astron.) (a) The arc of the horizon between the true east or west point and the center of the sun, or a star, at its rising or setting. At the rising, the amplitude is eastern or ortive: at the setting, it is western, occiduous, or occasive. It is also northern or southern, when north or south of the equator. (b) The arc of the horizon between the true east or west point and the foot of the vertical circle passing through any star or object. 4. (Gun.) The horizontal line which measures the distance to which a projectile is thrown; the range. 5. (Physics) The extent of a movement measured from the starting point or position of equilibrium; -- applied especially to vibratory movements. 6. (math.) An angle upon which the value of some function depends; -- a term used more especially in connection with elliptic functions. Magnetic amplitude, the angular distance of a heavenly body, when on the horizon, from the magnetic east or west point as indicated by the compass. The difference between the magnetic and the true or astronomical amplitude (see 3 above) is the "variation of the compass."
Mag*net"ic\, Magnetical \Mag*net"ic*al\, a. [L. magneticus: cf. F. magn['e]tique.]1. Pertaining to the magnet; possessing the properties of the magnet, or corresponding properties; as, a magnetic bar of iron; a magnetic needle. 2. Of or pertaining to, or characterized by, the earth's magnetism; as, the magnetic north; the magnetic meridian. 3. Capable of becoming a magnet; susceptible to magnetism; as, the magnetic metals. 4. Endowed with extraordinary personal power to excite the feelings and to win the affections; attractive; inducing attachment. She that had all magnetic force alone. --Donne. 5. Having, susceptible to, or induced by, animal magnetism, so called; as, a magnetic sleep. See Magnetism. Magnetic amplitude, attraction, dip, induction, etc. See under Amplitude, Attraction, etc. Magnetic battery, a combination of bar or horseshoe magnets with the like poles adjacent, so as to act together with great power. Magnetic compensator, a contrivance connected with a ship's compass for compensating or neutralizing the effect of the iron of the ship upon the needle. Magnetic curves, curves indicating lines of magnetic force, as in the arrangement of iron filings between the poles of a powerful magnet. Magnetic elements. (a) (Chem. Physics) Those elements, as iron, nickel, cobalt, chromium, manganese, etc., which are capable or becoming magnetic. (b) (Physics) In respect to terrestrial magnetism, the declination, inclination, and intensity. (c) See under Element. Magnetic equator, the line around the equatorial parts of the earth at which there is no dip, the dipping needle being horizontal. Magnetic field, or Field of magnetic force, any space through which magnet exerts its influence. Magnetic fluid, the hypothetical fluid whose existence was formerly assumed in the explanations of the phenomena of magnetism. Magnetic iron, or Magnetic iron ore. (Min.) Same as Magnetite. Magnetic needle, a slender bar of steel, magnetized and suspended at its center on a sharp-pointed pivot, or by a delicate fiber, so that it may take freely the direction of the magnetic meridian. It constitutes the essential part of a compass, such as the mariner's and the surveyor's. Magnetic poles, the two points in the opposite polar regions of the earth at which the direction of the dipping needle is vertical. Magnetic pyrites. See Pyrrhotite. Magnetic storm (Terrestrial Physics), a disturbance of the earth's magnetic force characterized by great and sudden changes. Magnetic telegraph, a telegraph acting by means of a magnet. See Telegraph.
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