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Electrical elements are conceptual abstractions representing idealized electrical components, such as resistors, capacitors, and inductors, used in the analysis of electrical networks. Any electrical network can be analysed as multiple, interconnected electrical elements in a schematic diagram or circuit diagram, each of which affects the voltage in the network or current through the network. These ideal electrical elements represent real, physical electrical or electronic components but they do not exist physically and they are assumed to have ideal properties according to a lumped element model, while components are objects with less than ideal properties, a degree of uncertainty in their values and some degree of nonlinearity, each of which may require a combination of multiple electrical elements in order to approximate its function. Circuit analysis using electric elements is useful for understanding many practical electrical networks using components. By analyzing the way a network is affected by its individual elements it is possible to estimate how a real network will behave. ==Types== Circuit elements can be classified into different categories. One is how many terminals they have to connect them to other components: *''One-port elements'' - these represent the simplest components, that have only two terminals to connect to. Examples are resistances, capacitances, inductances, and diodes. *''Multiport elements'' - these have more than two terminals. They connect to the external circuit through multiple pairs of terminals called ports. For example, a transformer with three separate windings has six terminals and could be idealized as a three-port element; the ends of each winding are connected to a pair of terminals which represent a port. * *''Two-port elements'' - these are the most common multiport elements, which have four terminals consisting of two ports. Elements can also be divided into active and passive: *''Active elements'' or ''sources'' - these are elements which can source electrical power; examples are voltage sources and current sources. They can be used to represent ideal batteries and power supplies. * *''Dependent sources'' - These are two-port elements with a voltage or current source which is proportional to the voltage or current at a second pair of terminals. These are used in the modelling of amplifying components such as transistors, vacuum tubes, and op-amps. *''Passive elements'' - These are elements which do not have a source of energy, examples are diodes, resistances, capacitances, and inductances. Another distinction is between linear and nonlinear: *''Linear elements'' - these are elements in which the constituent relation, the relation between voltage and current, is a linear function. They obey the superposition principle. Examples of linear elements are resistances, capacitances, inductances, and linear dependent sources. Circuits with only linear elements, linear circuits, do not cause intermodulation distortion, and can be easily analysed with powerful mathematical techniques such as the Laplace transform. *''Nonlinear elements'' - these are elements in which the relation between voltage and current is a nonlinear function. An example is a diode, in which the current is an exponential function of the voltage. Circuits with nonlinear elements are harder to analyse and design, often requiring circuit simulation computer programs such as Spice. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「electrical element」の詳細全文を読む スポンサード リンク
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