An important law to establish the relationship between current, voltage and resistance was given by Georg Ohm which was named as Ohm’s law which is given as follows-
V= I * R
Where V stands for voltage, I for current and R for resistance.
While designing the electrical devices it is important to keep in mind the ohm’s law such that the current and voltage of them are within specifications.
Conductors are of two types namely, ohmic conductors and non-ohmic conductors. Ohmic conductors are the conductors that follow Ohm’s law that is their resistance remains the same on changing the current and voltage.
Ohmic vs Non-Ohmic Conductors
The difference between Ohmic and Non-Ohmic conductors is that the ohmic conductors are the ones that follow Ohm’s law, that is, they have a constant resistance when the current across them is increased or the voltage in them is varied while non-ohmic conductors are those that do not follow ohm’s law, that us, their resistance varies with varying conditions of current, voltage and temperature.
Comparison Table
| Parameter of Comparison | Ohmic Conductors | Non-Ohmic Conductors |
|---|---|---|
| Basic definition | The ohmic conductors follow ohm’s law, which implies that the resistance of the conductors remains constant on varying current and voltage. | The non-ohmic conductors do not follow ohm’s law, that means the resistance of the conductor varies on sharing current, voltage and temperature. |
| Relationship between current and voltage | In the ohmic conductors, the current and voltage are directly proportional to each other, that is, there is a linear relationship between current and voltage. | In the non-ohmic conductors, the current and voltage are not directly proportional to one another, that is, current and voltage have a non-linear relationship between them. |
| The slope between current and voltage | The slope between current and voltage in ohmic conductors is a straight line. | The slope between the current and the voltage in non-ohmic conductors is not straight but a curved line. |
| Effect on temperature variations | Conductors follow ohm’s law when the temperature is in the range for which the conductor has been made but as the temperature increases, ohmic conductors also behave as non-ohmic conductors. | In non-ohmic conductors, the resistance of the conductors varies according to the variation in the temperature. |
| Examples | Examples of ohmic conductors are metals, resistors, nichrome wires, etc. | Examples of non-ohmic conductors are diodes, semiconductors, electrolytes, thyristors, transistors, filament lamps, etc. |
What are Ohmic Conductors?
The ohmic conductors follow ohm’s law implying that the resistance of the conductor remains constant while varying current and voltage. In other words, it can be said that the relationship between the current and the voltage is linear.
When plotted on a graph, the slope of the current and voltage for ohmic conductors comes out to be a straight line. One of the drawbacks of the ohmic conductors is that they lose their properties when they are operated in ranges other than specified.
The examples of the ohmic conductors are metals, resistors, etc. When the current flows through the resistor, it is directly proportional to the voltage or it can be said that they have a linear relationship.
What are Non-ohmic Conductors?
The non-ohmic conductors are those which do not follow ohm’s law. Not following ohm’s law means that their resistance is variable, it varies according to the change in current, voltage of temperature.
Graphically speaking, the slope of the current and voltage for non-ohmic conductors is not a straight line but it is a curved line. The properties of non-ohmic conductors also vary according to the change in temperature.
In filament lamps, if the voltage is continuously increased but the currents doesn’t increase beyond a particular value then it is said to be non-ohmic.
Main Differences Between Ohmic and Non-Ohmic Conductors
- Conductors follow ohm’s law only in the temperature range for which they are designed, they lose their properties when operated on a higher temperature which is more than the specified range while in non-ohmic conductors the resistance of the conductor varies with the varying temperature.
- Examples of ohmic conductors are metals and resistors while the examples of non-ohmic conductors are diodes, transistors, semiconductors, etc.
References
- https://www.sciencedirect.com/science/article/pii/002230937290227X
- https://www.tandfonline.com/doi/abs/10.1080/14786445008560976
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