what are linear elements

[ABEL DANIEL]

what is meant by linear electrical element?why is it called so??can we conclude that every curve passing through origin represents a linear function?

 

[chuckey]

A linear element has a linear voltage current relationship. No the V/I plot of a diode passes through the origin, buts its not linear, it just means that when V = zero, I = zero, i.e. it contains no source of voltage.
Frank

 

[LvW]

In addition to Frank`s explanation I like to add that his answer does apply also to non-linear voltage-current relationships that show within a certain and limited range a linear behaviuour.
In this case, we speak about small-signal conditions and the property of linearity applies to differential signals only (acting around a suitable dc bias point).
This applies, for example, to all tansistor amplifiers and - with some restrictions - also to pn-diodes.

 

[permute]

what is meant by linear electrical element?why is it called so??can we conclude that every curve passing through origin represents a linear function?

Linear, from a technical sense, means that f(a*x + b*y) = a*f(x) + b*f.

While this might seem simple to understand, there are several mathematical operations that meet this requirement and that might not be immediately obvious. Integration and differentiation from calculus are linear in this respect. Capacitors and inductors are therefore linear elements, as they perform these operations on voltages/currents.

Diodes and other elements do not meet this requirement, and are called "nonlinear". In theses cases, f(a*x) != a*f(x), and more generally f(a*x + b*y) != a*f(x) + b*f.