Ohm's Law

Introduction:

                    One of the most basic and important laws of electric circuits is Ohm’s law.Ohm’s law deals with the relationship between current, voltage and resistance.  

                    Georg Simon Ohm, a German physicist was the first to verify Ohm’s law experimentally. That is why the law is well known as Ohm’s law. Ohm’s law first appeared in the book written by Georg Simon Ohm in 1827.

Statement:

                    Ohm’s law states that "At constant temperature the voltage across a conductor is directly proportional to the current flowing through that conductor".

V ∝ I

                    The proportionality constant is written as 'R' and this is the resistance value of the conductor.

V= R × I

Formulas:


1. When a known voltage is applied across a known resistance the current through the resistance can be determined by the relationship 


2. When a known voltage is applied across a resistance and the current through the resistance is also known then the value of the reactance can be determined by the relationship


3. When a known current flows through a known resistance the voltage appeared across the resistance can be determined by the relationship


Limitation of Ohm’s Law:
  • Ohm’s law is not applicable in unilateral networks. Unilateral networks allow the current to flow in one direction. Such types of network consist elements like a diode, transistor, etc.
  • It is not applicable for the non-linear network. In the nonlinear network, the parameter of the network is varied with the voltage and current. Their parameter likes resistance, inductance, capacitance and frequency, etc., not remain constant with the times. So ohms law is not applicable to the nonlinear network.




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