# Question about power series relation of current and voltage in non linear circuit

#### silv3r.m00n

Joined Apr 15, 2010
70
Hi

I read in a book that in a non linear circuit the relation between the current and voltage involves the power series like this :

I = a1.V + a2.V^2 + a3.V^3 + a4.V^4 ...

how is this relation derived for a circuit ?

#### crutschow

Joined Mar 14, 2008
27,198
how is this relation derived for a circuit ?
It entirely depends upon the nature of the non-linear circuit.
For example, a junction diode has a logarithmic relation between the voltage across it and the current through it.