Direct current circuit

1. Mar 18, 2008

zvee_y

I've attached the problem in this post, so that's way yall can see the problem and picture easily.

3. The attempt at a solution

what is this signal $$\sum$$ means in the problem?
THe problem said they find the ammeter in the cirucuit read 2A, I just wonder is it the total current?
If i set up I = I1 + I2, then in loop 1 (top loop) I can use I and I1 to; and in loop 2(bottom loop) I can use I and I2 in order to find the currents. Is it correct? Please give me a hint. Thank you!!

Last edited: Mar 18, 2008
2. Mar 18, 2008

mgb_phys

The symbol is a capital Sigma, it generally means sum of ( ie add them all up )
ps - You don't seem to have attached the picture properly

3. Mar 22, 2008

zvee_y

4. Mar 22, 2008

kamerling

define the potential to the point to the right of the ammeter to be 0.
call the potential to the left of th 5 ohm resistance U.
What must U be to make the current through the ammeter equal to 2A?
Once you have U you can calculate I_1 and the use kirchhof's current law to get I_2

5. Mar 22, 2008

Snazzy

Go around the bottom loop and go around the top loop using Kirchoff's loop law, then find I3 through the ammeter in terms of I1 and I2. 3 equations and 3 unknowns.

6. Aug 8, 2008

kinnee2000

I want answer for questions, wuold you help mme?

7. Aug 8, 2008