# Homework Help: Voltage drop over dependent current source?

1. Sep 15, 2011

### Inertigratus

I have a circuit with 3 meshes for which I have to find the mesh currents, and I have.
However, I just thought that there might be a voltage drop over the dependent current source in the circuit, which would change the mesh current equations.
The CCCS is shared by two meshes.
When I did the calculations I simply ignored the CCCS.
Any ideas?

2. Sep 15, 2011

### Staff: Mentor

Can you post the circuit diagram?

3. Sep 15, 2011

### Inertigratus

Sure, http://img692.imageshack.us/img692/7081/namnlskei.jpg [Broken]
I'm not asking for the solution, just wondering what I should do with the dependent source when writing the mesh equations?

Last edited by a moderator: May 5, 2017
4. Sep 15, 2011

### Staff: Mentor

Two suggestions. First, you could convert the current source and the 4R resistor in parallel with it to a Thevenin equivalent voltage source. That would let you write the KVL mesh equations without worrying about mystery voltages. It would also reduce the circuit to just two loops.

Second, you could introduce a new variable, say vx, which is the voltage drop across the current source, and one new equation (with a new variable you need another equation). This equation would be the additional constraint on the mesh currents implied by the current source, namely i2 - i3 = k*i1.

I think that the first suggestion would be simpler. Note that the third mesh current i3 is strictly dependent upon the voltage vx via Ohm's Law with the 4R resistor.

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5. Sep 15, 2011

### Inertigratus

I see, thanks!
So it's possible to use ThÃ©venin and Norton equivalents when the sources are dependent as well?

6. Sep 15, 2011

### Staff: Mentor

Sure, as long as you maintain the dependencies through the calculations.