Electric Circuit with Equal Resistances: How to Determine Currents?

[imranmuhammad]

Homework Statement

The Problem Statement :

All resistances are equal and worth to 360 ohm

1°)We set between A et B a source of tension E ; E=U_A_B=12 volts,
Determine the intensities of the current in all resistances in this electric circuit.

2°)Take again question 1 but this time the source of tension is setted between A and D

3°) Take again question 1 and 2 the source of tension is replaced by a current source delivering an intensity of 20 milliamperes.

The electrical circuit for solve this problem :

[URL=http://img388.imageshack.us/my.php?image=sanstitredu6.jpg][PLAIN]http://img388.imageshack.us/img388/5952/sanstitredu6.th.jpg[/URL]http://g.imageshack.us/thpix.php [/PLAIN]

Homework Equations

I Haven't idea because I don't understand this lesson. I want absolutely that anyone help me please.

The Attempt at a Solution

I need Help because tomorow I Have test but I don't understand this exercise. Thank You

 

[-Vitaly-]

Problems like that can always be solved with 2 Kirchhoffs Laws. Define currents across resistances as I₁, I₂... and the total current I. Then use V=IR. and http://theory.uwinnipeg.ca/physics/curr/node8.html" to get a number of equations for currents, which you can solve simultaneously.
This always works.
But there are some other methods, e.g. considerations of symmetry, or Thevenin, Norton theorems.. etc