Ohmic vs Non-Ohmic Conductors
Ohm’s law, discovered and named after Georg Ohm, states the relationship between voltage, current and resistance of a conductor. This is important in designing electrical and electronic circuits in order ensure that the voltages and currents in the components stay within specs. Just about any component that is capable of carrying a current is considered to be a conductor, it’s just a matter of whether the conductor is Ohmic or not. The main difference between an Ohmic and a non-Ohmic conductor is whether they follow Ohm’s law. An Ohmic conductor would have a linear relationship between the current and the voltage. With non-Ohmic conductors, the relationship is not linear.
A good example of an Ohmic conductor is the resistor. The voltage drop across a resistor is directly correlated to the current that is flowing through it. But, this is only true when the resistor is kept within the temperature range that it is rated for. As more current flows through a resistor, it generates more and more heat. This heat, when it becomes excessive, can cause the resistor to become non-Ohmic and the resistance would also increase. Even ordinary wires are also considered as Ohmic conductors. Ordinary wires still have resistance but are often designed to be extremely low to minimize losses.
Non-Ohmic conductors do not follow Ohms law and have their own characteristics. There are a number of examples of non-Ohmic conductors; including bulb filaments and semiconductors like diodes and transistors. Let’s take the diode. A diode provides a near constant voltage drop even if you vary the current, so it does not follow Ohm’s law. The opposite happens in a light bulb filament; even as you increase the voltage significantly, it only allows a certain amount of current to pass through.
Even if non-Ohmic conductors do not follow Ohm’s law, they have their own specialized uses that aid greatly in electrical and electronic circuits. Incandescent light bulbs have been lighting our homes for more than a century and semiconductors have made a lot of things possible. Almost all electronic gadgets like phones, computers, even ordinary watches and remotes use semiconductors.
Summary:
1.Ohmic conductors obey Ohm’s low while non-Ohmic conductors don’t
2.Resistors tend to be Ohmic at its designed operating temperature
3.Semiconductors and bulb filaments are non-Ohmic conductors