indicator diagram

2 definitions found

indicator diagram - Collaborative International Dictionary of English v.0.48 :

  Indicator \In"di*ca`tor\ ([i^]n"d[i^]*k[=a]`t[~e]r), n. [L.: cf.
     F. indicateur.]
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     1. One who, or that which, shows or points out; as, a fare
        indicator in a street car.
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     2. (Mach.) A pressure gauge; a water gauge, as for a steam
        boiler; an apparatus or instrument for showing the working
        of a machine or moving part; as:
        (a) (Steam Engine) An instrument which draws a diagram
            showing the varying pressure in the cylinder of an
            engine or pump at every point of the stroke. It
            consists of a small cylinder communicating with the
            engine cylinder and fitted with a piston which the
            varying pressure drives upward more or less against
            the resistance of a spring. A lever imparts motion to
            a pencil which traces the diagram on a card wrapped
            around a vertical drum which is turned back and forth
            by a string connected with the piston rod of the
            engine. See Indicator card (below).
        (b) A telltale connected with a hoisting machine, to show,
            at the surface, the position of the cage in the shaft
            of a mine, etc.
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     3. (Mech.) The part of an instrument by which an effect is
        indicated, as an index or pointer.
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     4. (Zool.) Any bird of the genus Indicator and allied
        genera. See Honey guide, under Honey.
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     5. (Chem.) That which indicates the condition of acidity,
        alkalinity, or the deficiency, excess, or sufficiency of a
        standard reagent, by causing an appearance, disappearance,
        or change of color, as in titration or volumetric
        analysis.
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     Note: The common indicators are litmus, trop[ae]olin, phenol
           phthalein, potassic permanganate, etc.
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     Indicator card, the figure drawn by an engine indicator, by
        means of which the working of the engine can be
        investigated and its power calculated. The Illustration
        shows one form of indicator card, from a steam engine,
        together with scales by which the pressure of the steam
        above or below that of the atmosphere, corresponding to
        any position of the engine piston in its stroke, can be
        measured. Called also indicator diagram.
  
     Indicator telegraph, a telegraph in which the signals are
        the deflections of a magnetic needle, as in the
        trans-Atlantic system.
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  Diagram \Di"a*gram\, n. [Gr. ?, fr. ? to mark out by lines; dia`
     through + ? to draw, write: cf. F. diagramme. See Graphic.]
     1. (Geom.) A figure or drawing made to illustrate a
        statement, or facilitate a demonstration; a plan.
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     2. Any simple drawing made for mathematical or scientific
        purposes, or to assist a verbal explanation which refers
        to it; a mechanical drawing, as distinguished from an
        artistical one.
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     Indicator diagram. (Steam Engine) See Indicator card,
        under indicator
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