Characteristic Curve

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characteristic curve

[‚kar·ik·tə′ris·tik ′kərv]
(graphic arts)
In photography, a graph that shows how increases in exposure increase the density of the film.
(mathematics)
One of a pair of conjugate curves in a surface with the property that the directions of the tangents through any point of the curve are the characteristic directions of the surface.
A curve plotted on graph paper to show the relation between two changing values.
A characteristic curve of a one-parameter family of surfaces is the limit of the curve of intersection of two neighboring surfaces of the family as those surfaces approach coincidence.

Characteristic Curve

one of the most important indexes of a photographic material. It expresses (for specified exposure and developing conditions) the optical density obtained from photographic darkening of the material as a function of the common logarithm of the exposure that produced the darkening. (SeeSENSITOMETRY.)

Characteristic curve

A graphical display depicting complex nonlinear relationships in electronic circuits. A typical use is to show voltage-current relationships in semiconductor devices. Device amplification capabilities, for example, are exhibited by a characteristic plot which traces output current versus output voltage with a third controlling variable as a parameter. This control variable could be the base current of a bipolar junction transistor (BJT) or the gate-to-source voltage of a metal-oxide-semiconductor (MOS) transistor.

Other characteristics often included in transistor data sheets are displays of current gain versus bias current, gain versus frequency, and input and output impedances versus frequency. Less commonly, other graphical nonlinear relationships, such as the variation of thermocouple voltage with temperature or the dependence of electrical motor torque with current, also are known as characteristic curves.

In the past, characteristic curves were used as tools in the graphical solution of nonlinear circuit equations that are followed by relationships of this type. In current practice, this analysis is performed using computer packages for circuit simulation. Designers still use characteristic curves from data sheets, however, to evaluate relative performance capabilities when selecting devices, and to provide the information needed for a preliminary pencil-and-paper circuit design. See Amplifier, Transistor

References in periodicals archive ?
In fact, the power source should provide a broad range voltage output and usually a high-power margin dependent on its output voltage-current characteristic curve.
Line 1 is characteristic curve of the fan at the speed [N.
Two sets of characteristic curves are generally used to represent the turbine characteristics.
Figure 2, A and B, illustrates the receiver operating characteristic curves for FIT results and colorectal carcinoma for FIT results and colonic adenoma.
Under an IRT model, the person's trait level is estimated from the person's responses to individual items and the 'performance' of each item can be evaluated using item parameters depicted in item characteristic curves, item information curves, and test information curves.
Device characteristic curve based (DCCB) virtual sensors use device characteristic curves to relate the virtual measurements (consequential output of the device movements) to the input sensor measurements, which quantify device operation, as shown in Equation (1).
2002: Measurement of soil-water characteristic curves for fine-grained soils using a small-scale centrifuge.
True score equating is easier to implement as it involves test characteristic curves from two forms.
There are two main ways of using characteristic curves.
This occurs by the fact that low values of a indicate that the item has low discrimination power (individuals with quite different purchasing power have the same probability to possess the asset) and very high values with quite steep characteristic curves discriminate the individuals in basically two groups: those who have abilities below parameter b value and those who have abilities above parameter b value.

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