Combined Series-Parallel Circuits Study Guide


A combined series-parallel circuit is a type of circuit connected in both series and parallel. The pathways are designed as the hardest electric series and parallel combination circuits. All the components of this circuit are connected end to end, forming a parallel flow of the circuit. 


  • The current remains the same throughout the circuit. 
  • The sum of voltage all across the three resistors is equal to the other points’ voltage. 
  • It follows the rule of thumb.



We know that this circuit is neither a series nor a parallel, but it has the elements of both. This circuit has many paths for the current like in the parallel circuit, but there exists two sets of common points in the circuit. While solving the series-parallel combination circuit equation, you need to calculate the total resistance in both parts. To get a clear idea of how these circuits work, refer to the below given series and parallel circuit combined example.

series and parallelSource 


  • There is no definite formula for series and parallel circuit combination.
  • So for calculating the average resistance of a series-parallel circui, we have to find the resistance by solving the resistance of parallel and series sections separately and combining them to find the right value of resistance.
  • Further, to calculate the resonance frequency of the combined series-parallel circuit, we need to combine the formulas of both.



  • The combination circuits are a type of mixed circuit that follows a unique path. Some flow through a single resistor path, while some flow in parallel through two or more points. 
  • The combination series-parallel circuit has equal voltage all across the circuit. 
  • Currents remain equal throughout the circuit.



1. How do you solve combined parallel and series circuits?

To solve these circuits, follow these instructions: 

  • See which resistors are used in the circuit
  • Redraw the circuit until the circuit completes and gets reduced to the one equivalent resistor. 
  • Calculate current using Ohm’s Law.
  • Calculate the power dissipations.


2. What is the series-parallel combination?

It is a unique type of circuit that is connected in both series and parallel ways. The current remains the same throughout the circuit, and the sum of voltage all across the three resistors is equal to the other points’ voltage.

3. What are the examples of series-parallel combinations?

Some examples are- 

  • Strong Christmas lights
  • Light bulbs
  • Multiplexer
  • Wiring of car headlights
  • Comparator

4. What is the formula for series-parallel combinations?  

Parallel circuit: 

1/Rt = 1/R1 1/R2 1/R3 … Rt = R (t)total

Series circuit:

 Total Resistance = R1 R2 R3……so on

5. What are the rules for series and parallel circuits?

  • The combination circuit follows the rule of thumb. 
  • The outside current is the same throughout the circuit. 
  • The inside current is always less than the outside current.


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  1. Combination Circuits: Accessed 19th April 2022.
  2. Series-Parallel Circuits: Accessed 19th April 2022.
  3. Direct Current: Accessed 19th April 2022.
  4. What is a Series-Parallel Circuit? Accessed 19th April 2022.

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