Resistors in series

When resistors are connected in series, the amount of the current passing through all the resistors will be same but the voltage drops across the resistors may vary. For series connected resistors their resistance adds up. Their equivalent resistance is equal to the sum of all the resistors in series. Thus for a series connection, equivalent resistance increases with increase in number of resistors.

Consider the following circuit of three resistors
of resistance R₁,R₂ and R₃ respectively connected in series.

Series connection of resistors

The below figure shows the equivalent circuit with their equivalent resistance R_eq. It is given by,

R_eq= R₁+R₂+R₃.

equivalent resistance

Similarly if there n resistances each of resistance R are connected in series then their equivalent resistance is nR.