Classification of resistors

Question 1

How many types of resistance do we have?

Answer 1

Ohmic and non-ohmic

Question 2

What happens in the Ohmic resistor?

Answer 2

In an Ohmic resistor, the division of voltage and current are always constant. So voltage-against-current graph follows a constant slope (linear graph).

Question 3

What happens in an non-Ohmic resistor?

Answer 3

In an non-ohmic resistor, voltage-against-current graph is a curved line. So the gradient of the graph doesn’t give the resistance (which ohmic’s gradient does).

Question 4

How are the graphs of Ohmic and non-ohmic resistors?

Answer 4

The graph of ohmic resistor’s gradient is straight with a formula of R= V/I or 1/R= I/V.
Therefore, for non-ohmic, the line could have different shapes, and doesn’t have a constant gradient.