What is the difference between ohmic and non-ohmic conductors?

Ohmic conductors obey Ohm's Law, while non-ohmic conductors do not.

Ohmic conductors are materials that have a constant resistance when a voltage is applied across them. This means that the current flowing through an ohmic conductor is directly proportional to the voltage across it, as described by Ohm's Law: \( V = IR \), where \( V \) is voltage, \( I \) is current, and \( R \) is resistance. Common examples of ohmic conductors include most metals like copper and aluminium, which maintain a linear relationship between voltage and current.

Non-ohmic conductors, on the other hand, do not follow Ohm's Law. Their resistance changes with the applied voltage or current. This means the relationship between voltage and current is not linear. Examples of non-ohmic conductors include diodes, transistors, and filament bulbs. For instance, in a filament bulb, the resistance increases as the temperature of the filament increases, causing the current to not increase proportionally with the voltage.

In practical terms, if you were to plot a graph of current versus voltage for an ohmic conductor, you would get a straight line. For a non-ohmic conductor, the graph would be a curve. This difference is crucial in designing and analysing electrical circuits, as it affects how components behave under different electrical conditions.

Understanding the distinction between ohmic and non-ohmic conductors helps in predicting how different materials will respond in a circuit, which is essential for both theoretical studies and practical applications in physics and engineering.