I'm trying to understand how to calculate resistance in simple mixed parallel and series resister circuit. Below is a question from a worksheet I've been playing with to better understand the topic (Question 5 ->Figure 6).

Simple Resister Circuit

I can see the 220Ω and 100Ω resistors are in parallel, but I do not understand how to break out and calculate the 470Ω and 330Ω resistors.

The answer given is 80.54 Ω, but I cannot seem to reach this on my own.

How do I calculate the resistance between points A and B?

Source: AllAboutCircuits.com - Series-Parallel DC Circuits Worksheet


1 Answer 1


Try re-drawing the schematic:


simulate this circuit – Schematic created using CircuitLab

Hopefully the solution will be obvious once you do so (comment/ask if it's not).

  • \$\begingroup\$ This was very useful, thank you. Will absolutely try redrawing first in the future. Next on my list is LaTeX, but here is what I ended up with that worked exactly as expected: Resistance = (1/((1/((((1/((1/350)+(1/470)))+220)))+(1/100)) \$\endgroup\$
    – Citricguy
    Mar 25, 2013 at 6:03
  • \$\begingroup\$ You're answer led me to another question regarding the location of the 470 ohm resistor. electronics.stackexchange.com/questions/62263/… \$\endgroup\$
    – Citricguy
    Mar 25, 2013 at 6:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.