Discussion in 'Homework Help' started by Petrucciowns, Jun 17, 2009.

1. ### Petrucciowns Thread Starter Active Member

Jun 14, 2009
62
0
I am going through all my old homework and creating notes. (I know I should have taken notes in the past) Can anyone help me understand how the following answers were calculated. I looked under the DC section on All about circuits and didn't find any tutorials.
Thanks for any help.

http://img171.imageshack.us/img171/1062/exam33.jpg

2. ### StayatHomeElectronics AAC Fanatic!

Sep 25, 2008
1,021
71
To start you seem to be given Ib = 10 mA. Ib is across R3. You also seem to be given the the voltage across R3 is 100V. So, R3 = 100V / 10 mA. Voltages at each node in the diagram given in the problem, unless I am reading the diagram wrong. Find the voltage across the individual resistors. Add the currents from the different paths into the nodes and, therefore, through the resistors. Then use R = V / i.

What is the voltage across R2? 150V - 100V = 50V
What is the current through R2? Ib + I(L3) = 10mA + 20mA = 30 mA
What is R2?

Continue with the same method until the problem is solved...

3. ### Petrucciowns Thread Starter Active Member

Jun 14, 2009
62
0
I really appreciate your time to help me out. I remember now thank you so much.