AC Electric Circuits
Series-Parallel Combination AC Circuits
26 questions By Tony R. Kuphaldt
-
Question 4 of 26
Determine an equivalent parallel RC network for the series RC network shown on the left:

Note that I have already provided a value for the capacitor’s reactance (XC), which of course will be valid only for a particular frequency. Determine what values of resistance (R) and reactance (XC) in the parallel network will yield the exact same total impedance (ZT) at the same signal frequency.
Reveal answerR = 150 Ω
XC = 200 Ω
Follow-up question: explain how you could check your conversion calculations, to ensure both networks are truly equivalent to each other.
Notes:This problem just happens to work out with whole numbers. Believe it or not, I chose these numbers entirely by accident one day, when setting up an example problem to show a student how to convert between series and parallel equivalent networks!
-
Question 5 of 26
Determine the total impedance of this series-parallel network by first converting it into an equivalent network that is either all-series or all-parallel:

Reveal answerEquivalent series resistance and reactances:

Ztotal = 2.638 kΩ
Notes:Although there are other methods of solving for total impedance in a circuit such as this, I want students to become comfortable with series/parallel equivalents as an analysis tool.
-
Question 6 of 26
Determine the equivalent parallel-connected resistor and inductor values for this series circuit:

Also, express the total impedance of either circuit (since they are electrically equivalent to one another, they should have the same total impedance) in complex form. That is, express Z as a quantity with both a magnitude and an angle.
Reveal answerRparallel = 2092 Ω
Lparallel = 1.325 H
Ztotal = 1772 Ω ∠ 32.14o
Notes:There are different methods of solving this problem. Use the discussion time to let students expound on how they approached the problem, pooling together their ideas. Their creativity may surprise you!
Related Tools:
- Algebraic Substitution for Electric Circuits
- Performance-Based Assessments for Basic Electricity Competencies



