Explain the parallel connection of resistance and drive the formula of equivalent resistance.

When more than one resistances are connected across two points in the circuit such that more than one paths are available for the current to flow and voltage drops across two ends of each resistor are same, then the resistors are said to be connected in parallel between these two points.

From the figure above, suppose the current flowing through resistors R₁, R₂ & R₃ are I_1, I₂ & I₃ respectively.

Hence, I = I₁ + I₂ + I₃

Using Ohm’s Law,

And

From the equations we get,