Ohm’s Law

Ohm’s Law can be used to solve simple electric circuits with closed loop , loads and at least one voltage source; Ohm’s law is the base for the large collection of DC network theorems , AC Theorems and formulas. A lot of theorems , formulas and concepts in electronics are derived Using ohms law as the base. Using Ohm’s Law we can easily find the relationship between Current , Resistance and Voltage in a simple circuit.

Ohm’s Law was invented by German physicist Georg Ohm in 1827 ans states that:

The ratio of potential difference (V) between two points in a conductor to the current (I) flowing between them , is constant , provided that the temperature of the conductor does not change. 

Or  Mathematically:

\dfrac{V}{I} = Constant Or , \dfrac{V}{I} = R

Where “R” is a constant and is is the resistance of the conductor between two points considered.

In other words the Ohm’s Law can be summarized as:

If the resistance of the load is kept constant in a circuit then the amount of current flowing through the circuit is directly proportional to the Potential difference or voltage applied to the circuit.

Note: This proportionality of voltage and current only applies in linear devices such as resistors. In non linear devices like Silicon Diode , Capacitors the normal ohm’s law does not holds true instead their own version of ohm’s law is derived for various non linear devices.

Formula Variations of Ohm’s Law:

There are three variations of mathematical expression for Ohm’s Law as listed below:

1. R = \dfrac{V}{I}

2.  V = I \times R

3.  I = \dfrac{V}{R}

There three variations of formulas that can be used to solve for various unknown parameters in a circuit.
The first formula can be used when “V” and “I” are known but the Load resistance “R” is not known , the second can be used when “I” and “R” are known but Electromotive force applied “V” is not known and the third can be used when “V” and “R” are known but the current flowing through the circuit “I” is not known.

Graphical Representation of Ohm’s Law:

The ohm’s law states that the Current flowing through the circuit is directly proportional to the amount of Potential Difference applied if the load resistance is kept constant , this can be visualized with the following animation:

Ohm's Law
Ohm’s Law

Here , when the Potential difference of 0 voltage is applied the ammeter in the circuit reads 0 amps , when it is increased to 5 voltage the ammeter reads 1 amps which is verified using the formula   I = \dfrac{V}{R} and so on , which is in accordance with the ohm law which states that the current flowing the circuit is directly proportional to the potential difference applied when the resistance is kept constant.