1. Calculating Resistance in Series and Parallel Circuits
Basic Formulas for Rapid Computation of Circuit Resistance

2. Introduction Informational lecture by Fred Baker
Electronics Instructor for U.S. Navy

3. Topics of Discussion
Resistance totaling values, dependent on the circuit structure
Knowing how to calculate resistance depending on circuit structure
Understanding these basics can save valuable time and effort

4. Resistance Rules for Series Circuits
Series circuits are always one-for-one additive
Rt = R1 + R2 + R3 + Rn

5. Series Circuit
Sample of a Series Circuit layout R1 R2 R3

6. Solving for Series Resistance
Calculate the resistance using the series formula:
Rt = R1 + R2 + R3 + Rn
Rt = 20W + 30W + 50W = 100W
R1=20W
R2=30W
R3=50W

7. Resistance Rules for Parallel Resistance Circuit
Parallel circuits are reciprocally additive
Rt = 1
R R2 R3

8. Parallel Circuit Sample of a Parallel Circuit layout R1=20W R2=30W

9. Solving for Parallel Resistance
Calculate using reciprocal formula:
Rt = 1 / 1/R1 + 1/R2 + 1/Rn
Rt = 1/1/20W + 1/30W + 1/50W
Rt = 1/0.05W W W
Rt = 1/103W = 9.70W
R1=20W
R2=30W
R3=50W

10. Summary Determine the type of circuit layout you are working with
Apply the correct formula
Verify answer by double-checking math