Question

What are the limitations of Ohm's Law?

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Solution

**Ohm's law:**

Ohm’s law states that the electric current is proportional to the voltage and is inversely proportional to the resistance.

Mathematically, this current-voltage relationship is written as,

$\mathrm{V}=\mathrm{IR}$

Here,

V is voltage.

I is current.

R is resistance.

The same formula can be written in the order to calculate resistance and current as follows:

$\mathrm{I}=\frac{\mathrm{V}}{\mathrm{R}}$

$\mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}}$

**Limitations of ohm's law:**

- Ohm's law does not apply to unilateral electrical components such as diodes as well as transistors even though they only permit current just to flow in one way.
- Voltage level will not be constant with respect to time for non-linear electrical components with properties such as capacitance, resistance, and so on, making Ohm's law problematic to apply.

Example:

- A water volt-ammeter. It is an example of a unilateral network and Ohm’s law is not applicable to such networks.
- Semiconductors such as Silicon and Germanium don’t obey Ohm’s law and are known as Non-Ohmic conductors.

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