I have to calculate the resistance R_AB, R_AC and R_CD. But I'm confused because there are two different terminal, one on the left and one on the right. Can someone give me a hint how to solve this?
2 Answers
If you were to draw out the circuit with just the terminals mentioned you would get this.
The wood should now be separated from the trees.
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\$\begingroup\$ Hi thx for the pictures :) I understand it now. It was simple, but sometimes your thoughts need a push to thing about it differently. \$\endgroup\$ Commented Dec 8, 2015 at 19:13
Not sure why are you confused. For R_AB there are only two terminals, both on the left. For R_AC one is on the left and one on the right. For R_CD both are on the right.
You should just ignore unused terminals and solve the schematics using the rules of parallel and series resistors. Or Kirchgoff / Ohm laws.
For example for R_AB the C is ignored, you can erase it to the closest junction (but leave the resistors 10 and 10 connected). For R_AC you erase both B and C and then erase the 30 resistor since its bottom terminal is not connected anywhere.