Lesson 1. Reducing Series CircuitsSeries resistor circuits are the simplest to convert to an equivalent resistance. To determine the value of the equivalent resistor, you simply add the values of the individual resistors in the original circuit. If you know how to determine the total resistance of a series circuit, you already know how to find the equivalent resistance--they are one and the same. RT = R1 + R2 + R3 + ... + Rn

Example 1

Determine the equivalent resistance, R1, 2, for this two-resistor series circuit:

Solution

This is a series combination, so:

R1, 2 = R1 + R2

Where:
R1  and R2 are the given values
R1, 2 = equivalent resistance of the circuit
 Note Notice that we use the designation R1, 2 to indicate the equivalent, or combined,  resistance of resistors R1 and R2. This is a common convention, but not one that is universally accepted. You should use the convention specified by your instructor.

Example 2

Determine the equivalent resistance, R1, 2, 3 for this three-resistor series circuit:

Solution

This is a series combination, so:

R1, 2, 3 = R1 + R2 + R3

Where:
R1, R2, and R3 are the given values
R1, 2, 3 = equivalent resistance of the circuit