- #1
Rokas_P
- 19
- 0
I'm having problem trying to calculate total resistance in resistor arrangement like this one:
http://o3xn.files.wordpress.com/2012/04/different.png
Before I go into any more detail with the original problem, I just want to say that whenever I get this "closed" type of circuits, I like rearranging them into the "open" type, so that e.g.
http://o3xn.files.wordpress.com/2012/04/r_1_20120414.png
becomes
http://o3xn.files.wordpress.com/2012/04/r_2_20120414.png
-------
Okay, back to the original question. First, I observe that potential at point 2 is higher than at point 3, which means that the current flows from 2 to 3 ("down"). This in turn means that there are basically two (parallel) ways for the current to pass this circuit:
(the above both) first R, then either 5R or 2R-7R / the two subpaths are in parallel to one another
(the below path) first 2R, then 7R
This seems to indicate that I can redraw the circuit as follows:
http://o3xn.files.wordpress.com/2012/04/different2.png
This rearranged circuit is not entirely "open" (2R is connected to the wire in between 2R and 7R) and I have no idea how I should treat this.
One of my guesses was that perhaps I am allowed to add another 7R resistor, making the circuit look like this one:
http://o3xn.files.wordpress.com/2012/04/different3.png
I'm not sure if I can add the extra resistor if it wasn't in the original problem. But it does have two different currents flowing, so maybe?
http://o3xn.files.wordpress.com/2012/04/different.png
Before I go into any more detail with the original problem, I just want to say that whenever I get this "closed" type of circuits, I like rearranging them into the "open" type, so that e.g.
http://o3xn.files.wordpress.com/2012/04/r_1_20120414.png
becomes
http://o3xn.files.wordpress.com/2012/04/r_2_20120414.png
-------
Okay, back to the original question. First, I observe that potential at point 2 is higher than at point 3, which means that the current flows from 2 to 3 ("down"). This in turn means that there are basically two (parallel) ways for the current to pass this circuit:
(the above both) first R, then either 5R or 2R-7R / the two subpaths are in parallel to one another
(the below path) first 2R, then 7R
This seems to indicate that I can redraw the circuit as follows:
http://o3xn.files.wordpress.com/2012/04/different2.png
This rearranged circuit is not entirely "open" (2R is connected to the wire in between 2R and 7R) and I have no idea how I should treat this.
One of my guesses was that perhaps I am allowed to add another 7R resistor, making the circuit look like this one:
http://o3xn.files.wordpress.com/2012/04/different3.png
I'm not sure if I can add the extra resistor if it wasn't in the original problem. But it does have two different currents flowing, so maybe?