Ohm's Law | Statement, Derivation, Its Applications And Limitations

• Ohm's Law
• Why The Temperature Is Kept Constant In Ohm’s Law
• Applications of Ohm’s Law
• Limitations of Ohm’s Law:

Ohm's Law:

Ohm's Law states, that current through any conductor is directly proportional to the potential difference between its two ends, Temperature, and other physical quantities being constant

Potential difference ∝ Current
&nbsp &nbsp &nbsp &nbsp &nbsp V ∝ I
( When the value of V increases the value of I increases simultaneously)
&nbsp &nbsp &nbsp &nbsp &nbsp V = IR

where,

• V is Voltage in volts (V)
• I is Current in Ampere (A)
• R is Resistance in ohm (Ω)

Why The Temperature Is Kept Constant In Ohm’s law:

The main criteria for Ohm’s law is to keep the resistance constant because proportionality constant in the relationship is resistance R. But we know that the variation of temperature affects the value of resistance so to keep the resistance constant during experiments of Ohm’s law the temperature is considered constant.

Applications of Ohm’s Law:

There are thousands of applications of this law in our daily life. We will show only a few of them in this article.

• Conventional Domestic Fan Regulator is one very common device where the current through the fan gets regulated by controlling the resistance of the regulator circuit.
• In the voltage divider circuit, this law is used to divide source voltage across the output resistance.
• In electronic circuits, there are many purposes where intentional voltage drop is required to supply specific voltage across different electronic elements. This is done by applying Ohm’s law.
• In mainly dc ammeter and other dc measuring instruments shunt is used to divert current. Here also Ohm’s law is used.

The list will continue as much as you think.

Limitations of Ohm’s Law:

The limitations of Ohm’s law are explained as follows:

• This law cannot be applied to unilateral networks

  A unilateral network has unilateral elements like a diode, transistors, etc., which do not have the same voltage-current relation for both directions of current.

• Ohm’s law is also not applicable for non – linear elements

  Non-linear elements are those which do not have current exactly proportional to the applied voltage, which means the resistance value of those elements changes for different values of voltage and current. Examples of non – linear elements are thyristor, electric arc, etc.

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