Ohm's law

Ohm's law

Posted by Prabhat Jani on 20:11 in Basic Electrical Engg, Circuit Analysis, Electrical Laws

George Simon Ohm found that the voltage, V between two terminals of a current-carrying conductor is directly proportional to the current, I flowing through it. The proportionality constant, R is the resistance of the conductor. Thus, according to Ohm’slaw

This relation will hold good provided the temperature and other physical conditions do not change.

Figure 1.1 (a) Shows linear relationship between V and I; (b) V–I characteristics for different values of R

Ohm’s law is not applicable to nonlinear devices like Zener diode, voltage regulators, etc. Ohm’s law is expressed graphically on V and I-axies as a straight line passing through the origin as shown in Fig. 1.1 (a).

The relationship between V and I have been shown for different values of R in Fig. 1.1 (b). Here in V = RI, R indicates the slope of the line. The more the value of R is, the more will be the slope of the line as shown in Fig. 1.1 (b).