In series connection, the resistors are connected end to end as shown below:
In such a connection, the total resistance between the terminals A and B is the sum of individual resistances.
Rab = R1 + R2 + R3
Rab = total effective resistance in the circuit
For example, if a 2.2K ohm and 3.3K ohm resistors are connected in series, the total resistance is 2.2+3.3 = 5.5Kohm.
The Current through each resistor is the same. I1 = I2 = I3 = I
