Question

Describe and differentiate how the current through and resistance of a resistor would change as the potential difference across it changes for both ohmic and non-ohmic cases. (If you mention Ohm's law, explain its content.)

Answer 1

Answer explained in details in explanation.

Step-by-step explanation:

Ohm's law states that the current passing through a mettalic conductor is directly proportional to the ptotential difference across its end provided temperature and other physical properties remain constant.

Mathematically,

V = IR

Where,

V is applied voltage in Volts

I is current in Ampere

R is resistance in Ohms

All true Ohmic devices obey Ohms law. Example of ohmic devices are resistors, light filament etc. For an Ohmic device or component with resistance R, a proportional increase/decrease in the value of the applied voltage will cause a proportional increase/decrease in the current respectively. This implies the ratio of voltage to curremt, V/I, is constant. Considering a simple circuit with a ohmic device of constant resistance, when current, I, is plotted as a function of voltage the curve is a straight line (linear) graph.

However, there are components of electrical circuits which do not obey Ohm’s law. These components or devices are said to be non-ohmic. For non-hmic devices or components, with resistance R, a proportional increase/decrease in the value of the applied voltage will not cause a proportional increase/decrease in the current respectively. The relationship between current and voltage (I–V curve) is nonlinear for non-ohmic devices. An example is the p-n junction diode.