# Gain of a Circuit with a Dep. Current Source and Indep. Voltage Source

Discussion in 'Homework Help' started by saleenman, Sep 12, 2015.

1. ### saleenman Thread Starter New Member

Aug 16, 2011
2
0
Okay, so I've spent about the last 4 hours working on these two problems. I've used up more paper than I wish to admit trying to work these out. It's all amounted to nothing and I feel like I'm going in circles. It's also bothering me, since the professor for this class said we all should've done problems like these in our early DC Circuits class, but I don't remember doing anything exactly like these.

Any help would be greatly appreciated!

Thank you,
Austin Bartz

2. ### WBahn Moderator

Mar 31, 2012
18,087
4,917
You need to show the your best attempt at solving your homework -- we aren't here to solve it for you. By showing us your best attempt -- no matter how wrong it is -- we can see what you are doing right, what you are doing wrong, and gain some insight into how you are approaching the problems and what concepts you might be messing up.

3. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,501
511
Either Node-Voltage or Mesh-Current Methods would work on Number 3.

4. ### Russmax Member

Sep 3, 2015
81
12
For #3
All right. You get that Vx = Vo-Vs, right?
Write an equation for Vs around the outside loop, Vs = sum of voltages across Rs and Ro. Don't forget that Vx=Vo-Vs
Write an equation for Vo, the voltage across Ro.

Do not use the term I for current in either equation. All currents can be written as expressions of Vs, Vo, Rs, Ro, and g.

That should get you on the right track. You can get this in less than half a page.

5. ### Russmax Member

Sep 3, 2015
81
12
For #6
Dude, you're making this too hard, whatever you're doing.

The "Thevenin equivalent" of the circuit in 6 is easy because the circuit is already in Thevenin form. The answer is r*Is, but you don't get to use Is. What you need is to find an expression for r*Is in terms Vs, R, and r.

Write a loop equation for the left-side loop, and you will have that.