Electrical Element Article Index for
Electrical
Website Links For
Electrical
 

Information About

Electrical Element





ELEMENTS VS. COMPONENTS

There is a distinction between real, physical Electrical Or Electronic Component and the ideal electrical elements by which they are represented.
  • Electrical elements do not really exist, and are assumed to have ideal properties according to a Lumped Element Model .

  • Conversely, components do exist, have less than ideal properties, their values always have a degree of uncertainty, they always include some degree of nonlinearity and typically require a combination of multiple electrical elements to approximate their functions.

  • Circuit analysis using electric elements is useful for understanding many practical electrical networks using components.



THE ELEMENTS

Any electrical network can be analyzed algebraically if its components are represented by a combination the following elements. Only 5 elements are required to represent any component or network:

  • Two sources:

  • --- Current source, measured in Ampere s - produces a current in a conductor.

  • --- Voltage source, measured in Volt s - produces a Potential Difference between two points.

  • Three passive elements:

  • --- Resistance , measured in Ohms - produces a voltage proportional to the current flowing through it.

  • --- Capacitance , measured in Farad s - produces a current proportional to the rate of change of voltage across it.

  • --- Inductance , measured in Henries - produces a voltage proportional to the rate of change of current through it.



EXAMPLES

The following are examples of representation of components by way of electrical elements.
  • On a first degree of approximation, a battery is represented by a voltage source. A more refined model also includes a resistance in series with the voltage source, to represent the battery's internal resistance (which results in the battery heating and the voltage dropping when in use). A current source in parallel may be added to represent its leakage (which discharges the battery over a long period of time).

  • On a first degree of approximation, a resistor is represented by a resistance. A more refined model also includes a series inductance, to represent the effects of its lead inductance (resistors constructed as a spiral have more significant inductance). A capacitance in parallel may be added to represent the capacitive effect of the proximity of the resistor leads to each other. A wire can be represented as a low-value resistor

  • Current sources are more often used when representing Semiconductor s. For example, on a first degree of approximation, a bipolar Transistor may be represented by a variable current source that is controlled by the input voltage.




SEE ALSO

Electrical Or Electronic Component