-1
\$\begingroup\$

I found this circuit in a textbook, but I'm having a difficult time calculating the total resistance here. I tried using the formula for parallel resistors with the 3 resistors the the upper left, and then add that to the most right resistors. This would give me the total resistance of the upper half of the circuit. I then used that resistance, and used the formula for parallel circuits with the lower portion, but that gave me an incorrect answer.

The solution is supposedly 10ohm / 11.

enter image description here

\$\endgroup\$
  • \$\begingroup\$ This is recognizable as an application of a delta /wye transformation \$\endgroup\$ – placeholder Jun 6 '16 at 9:38
  • \$\begingroup\$ @placeholder it can be done still simpler by series/parallel transformations. R is 1 ohm. \$\endgroup\$ – Roger C. Jun 6 '16 at 9:42
  • \$\begingroup\$ @RogerC. you're no fun ... ;) \$\endgroup\$ – placeholder Jun 6 '16 at 9:47
  • \$\begingroup\$ @placeholder ok, I got it ;-) \$\endgroup\$ – Roger C. Jun 6 '16 at 12:57
2
\$\begingroup\$

If R=1, your approach is correct.

  1. 1 // 2 = 23

  2. 23 + 1 = 53

  3. 53 // 2 = 1011

1.

schematic

simulate this circuit – Schematic created using CircuitLab

2.

schematic

simulate this circuit

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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