Non-ohmic conductors, also known as non-ohmic materials or non-ohmic resistors, are materials that do not follow Ohm's Law, which states that the current passing through a conductor is directly proportional to the voltage applied across it, given a constant temperature.
In Ohm's Law, the relationship between voltage (V), current (I), and resistance (R) is given by the equation:
=
ā
V=Iā
R
For non-ohmic conductors, this relationship does not hold true. In other words, the resistance of these materials changes with varying voltage or current, or both. Unlike ohmic conductors (such as most metals) where the resistance remains constant over a wide range of voltages and currents, non-ohmic conductors exhibit behaviors that deviate from this linear relationship.
One common example of a non-ohmic conductor is a semiconductor, like silicon or germanium. As the voltage applied across a semiconductor increases, its resistance can change significantly due to the changing behavior of charge carriers within the material. This is the principle behind diodes, which are semiconductor devices that allow current to flow in one direction more easily than in the other.
Another example is a filament lamp (incandescent bulb). As the voltage across the filament increases, the filament's temperature rises, causing an increase in its resistance. This results in a non-linear relationship between voltage and current, making the lamp's behavior non-ohmic.
Non-ohmic conductors are often encountered in devices and circuits where their unique properties are intentionally exploited. They can be used for things like voltage regulation, rectification, temperature sensing, and more. Understanding the behavior of non-ohmic conductors is crucial for designing and analyzing circuits involving these materials.