Question

24. what r ohmic and non-ohmic conductors? explain with egs.?

Answer 1

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

Answer 2

In an Ohmic conductor the current flowing is proportional to the voltage applied. 
In a non-Ohmic conductor there is no linear relationship. 

Examples of Ohmic conductors are metals and carbon (as long as no significant heating occurs). 

Examples of non-Ohmic conductors are semiconductors, thermistors and filament light-bulbs.

Hope this helps:)