Circuit with switch.

Discussion in 'Homework Help' started by cdummie, Sep 18, 2015.

Feb 6, 2015
104
1
When the switch in the circuit is closed, then I=(3-j)A. Find complex power of Ig1 when the switch is off if we know that then, complex power of Ig2 is Sig2=(10+j6)VA.

Known values are: Z=(2-j2)Ohms , Z1=(1+j2)Ohms, Z2=Z4=(2+j4)Ohms, Z3=(2-j4)Ohms, Ig1=(0.5+j1.5)A and E=(7+j3.5)V.

In the first case, there's no impedance Z in the circuit, does it means that there's no Ig2 in the circuit since both ends of Ig2 are on the same potential or i'm wrong, i am not really sure about this because that would mean that Ig2 is zero and how then it's complex power can be (10+j6)VA?

RRITESH KAKKAR likes this.
2. WBahn Moderator

Mar 31, 2012
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4,807

Ig2 is a constant current source. By definition, whatever current it put out yesterday it is putting out today and it will put out tomorrow.

Feb 6, 2015
104
1
So how should i approach this, any hints?

4. shteii01 AAC Fanatic!

Feb 19, 2010
3,398
497
Mesh-Current Method or Node-Voltage Method, you pick one.

Feb 6, 2015
104
1
I though about that, but i don't know the values of E2, E3 and Ig2.

6. shteii01 AAC Fanatic!

Feb 19, 2010
3,398
497
You know power at Ig2 when switch is Off. So you can probably figure out Ig2.

E2 and E3... yeah, I would need to get some equations going to figure out if finding their values is possible.
I notice that you are not doing it, therefore I don't see any reason why I should.