INTRODUCTION-
STATEMENT-
Mathematically,
I ∝ V or V = I×R (R is a constant of proportionality)
Ohms law defines a very very important relation among voltage, current and resistance in any electrical circuit however this relation or law is not applicable in some cases stated under limitation. But this law can be applied to electric to electric conduction through good conductors. George Simon Ohm stated the Ohm’s law and it can be stated as follows...
STATEMENT-
At a constant temperature ,the current passing between the two points of a conductor is directly proportional to the potential difference existing between the two points.
OR
It simply means that provided R(resistance) is kept constant, current(I) is directly proportional to the potential difference(V) across the ends of a conductor.
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| OHM'S TRIANGLE |
I ∝ V or V = I×R (R is a constant of proportionality)
Electrical current in a conductor consists of movement of electrons. When electrons flow through a material they collide with other atomic particles and energy is lost in the form of heat due to these collisions and this is represented by resistance.
Resistance is the property of a material by virtue of which it opposes the flow of electrons (or current) through it. The opposition to flow of current is due to the above collisions of electrons inside the conductor.
LIMITATIONS OF OHMS LAW-
➤ This linear relationship between V and I does not apply to all non-metallic conductors
➤The temperature of the conductor should remain constant . Which is not possible because when there is a current flows through the conductor it generates heat due to inter- molecular friction.
However when we apply this law in any electrical or electronic circuit we assume that the temperature is constant.(which is not practical)
➤ In case of some electronic circuit components like diode , transistor etc. does not obey this law because if we plot V vs I characteristic of such element they represents a non linear curve that's why ohm's law doesn't validate in this case.