# Circuit Theory - Basic

1. Sep 7, 2006

### verd

Hey,

I'm having a bit of difficulty with this specific circuit theory problem... We understand the basics, Ohm's law, Kirchoff's voltage and current laws, voltage and current division... I'm just confused about what to do with this problem:

Find the value of Vx in the circuit below such that the power supplied by the 5-A source is 60W.

http://synthdriven.com/images/deletable/EEN201-03.jpg [Broken]

I mean, I figure I'd start with the 5A current source... P=IV, so the potential over that current source would be 12v? I don't know, I'm really confused. The shape of this thing has me confused as well, what's in parallel with what and what's in series?

Last edited by a moderator: May 2, 2017
2. Sep 7, 2006

### doodle

You didn't mentioned superposition, so I'll assume that it is part of the course too.

You could try to use superposition (of the 4 sources) to work out to the 12V across the 5A source. From there, it should be possible to know what value Vx is.

3. Sep 7, 2006

### verd

haven't been introduced to superposition yet...

4. Sep 8, 2006

### doodle

In which case, is it possible that you learn about the method and apply it on the problem? Here is a good place to start:

You could, of course, use something in the like of KVL or KCL to solve the problem, but I don't think it will be any easier than superposition.

Last edited by a moderator: May 2, 2017
5. Sep 8, 2006

### verd

we haven't learned superposition yet, this is an exercise to teach us how to use KCL KVL current division, voltage division and ohm's law to find values

i just don't know how to start this problem using KCL KCL current division, voltage division and ohm's law... not superposition... i'm confused with where to start

6. Sep 8, 2006