What is Ohm’s law and How is resistance equation calculated?

Ohm’s law states that voltage (V) across a conductor is proportional to the current (I) flowing through it, considering all physical conditions and temperatures remain constant. The most basic and important law of electric circuits is the Ohm’s Law. The law essentially describes a mathematical relationship between the voltage (V), current (I), and circuit resistance (R). The law was first experimented by George Ohm, the German physicist.

Georg Simon Ohm Mathematically, Ohm’s Law is written as: V = I * R Where,

• V is the Voltage (Potential Difference) measured in Volts.

To find voltage (V), V = I R V(volts) = (amps) R()

• It is the current flowing through the conductor.

To Find the current (I), I = V R I(amps) = V(volts) + R()

• R is the resistance of the circuit measured in Ohms (Ω).

To find the resistance (R), R = V I R= V volts) I(amps)

Calculating Resistance Equation using Ohm’s Law

Ohm’s Law equation is used to calculate the voltage, current and resistance of a circuit. The ohm’s law formula triangle is-

Ohms Law Triangle Now, To calculate the current in a circuit, rearrange the Ohm’s Law equation as- I = V / R

Similarly, you can calculate the electrical resistance of a circuit through- R = V / I

For a circuit to obey Ohm’s Law, Constant Resistance (R) is required.The  Electrical resistance in a circuit is affected by various physical factors, including temperature. The resistance increases as the temperature increases (such as copper wire), so Ohm’s Law does not hold true in that case. Limitations of Ohm’s Law Given below are the few examples where the Ohm’s law fails to apply:

1. A diode demonstrates the limitations of Ohm’s law. When the V vs I graph for a diode is plotted, it is observed that the relation between V and I is not linear. This happens when V is marked in a reverse direction so that the magnitude is fixed. The I is therefore produced in the opposite direction with a different magnitude.
2. Due to unilateral network, Ohm’s law is not applicable to a water volt-ammeter.
3. It is also not necessary that all the conductors obey Ohm’s law. Also, semiconductors like Germanium and Silicon do not