- #1

diredragon

- 323

- 15

## Homework Statement

(##R_5=8\Omega##)

a) Calculate the current ##I_{g2}## so that the power of the generator ##I_{g1}## equals ##P_{ig1}=6.25W##

b) What is ##I## then?

## Homework Equations

3. The Attempt at a Solution [/B]

First step: I change the last two branches with an equivalent thevenin's system.

##R_{t4}=\frac{R_4R_3}{R_2 + R_3}=12\Omega##

##E_{t4}=\frac{-E_4R_3}{R_3+R_4}=-15V##

(I have set the thevenin generator to have + sign pointing up)

Second step: I do the same with the remaining two right branches ( The thevenin system and the ##E_6## )

##R_{t6}=(R_{t4}+R_5)||R_6=10\Omega##

##E_{t6}=\frac{E_{t4}R_6+E_6(R_5+R_{t4})}{R_{t4}+R_5+R_6}=-2.5V##

Third step: Change the left part into the thevenin system

##R_{t1}=R_1=5\Omega##

##E_{t1}=I_{g1}R_1=5V##

DO you think that this is the right way to start and can you hint at what i should do in this problem? I'm thinking since ##P_{ig1}=6.25W=U_{ig1}I## that that power must equal the power of the generator i created to replace this? Is that right? So i can get the current that goes through the generator ##E_{t1}## Its ##I=\frac{6.25}{5}=1.25mA##? Is this good?