Introduction to Resistors

Resistors are key components in electric circuits, though they prevent electric current from flowing freely. They regulate both the amount of voltage and current during an application. When multiple resistors exist in a circuit, there are two major arrangements: series and parallel. Each of these has specific formulas for determining total resistance; that knowledge will form the basis of understanding circuits.

Resistors in Series

If resistors are connected in series, they are connected end-to-end, so the same current flows through each resistor. The total resistance (Rtotal) in a series circuit can be calculated using the following equation:

Where, 

• Rtotal​ is the total resistance,

• R1, R2, R3,…, Rn are the individual resistances of the resistors.

Parallel Resistors

Total Resistance Of 3 or more Resistors Connected parallel

For resistors that are connected in parallel, two points with multiple paths connecting these two points are used. Therefore, for the resistors connected in a parallel configuration, the equivalent resistance is given by the formula as follows;

Where, 

• Rt = Total Resistance

• R1 = Resistance 1

• R2= Resistance 2

• R3= Resistance 3

Total Resistance Of 2 Resistors Connected Parallel

Alternatively, for two resistors, the formula can be simplified to:

Where, 

• Rt= Total Resistance

• R1 = Resistance 1

• R2 = Resistance 2