If you prefer arrows in the diamonds, conventional current flows from + to - so an arrow can be asigned to replace the +/- signs in the diamond. The controlling equation of current is definitely related to another current, however.

But it is NOT a current source. It is a current-controlled voltage source (CCVS). Through some means, it senses the current ia. It then programs the voltage source to deliver 20V, positive at the bottom relative to the top, for each amp of current that is flowing in ia in the direction indicated.

 

Hi WBahn, the bottom line is my 0V reference node. I didn't include it or the 20 V/A*ia simply because it didn't include it in the problems sheet I was given by my lecturer (attached to my first post).

The problem didn't need to include it because it didn't need to reference it. But as soon as YOU (or anyone else) start talking about the voltage at a particular node, you have to indicate what other point that voltage is being referred to.

It is good practice to get in the habit of identifying the common node at the beginning of a problem. If one is not already indicated, you get to pick one. Any one will do, but some are better picks than others.

As for the problem not indicating the V/A, that is because, very sadly, most authors are inexcusably sloppy with units because they have never worked where sloppy units lead to anything other than missed points on a problem or exam. In the real world there are real consequences for errors made and/or not caught because of sloppy units and sometimes those consequences include unnecessary funerals.

If YOU will commit to using and tracking your units properly, then you will be amazed at the mistakes it will catch and how much your grades will improve.

 

Hi WBahn, i was wondering, do you know how to deal with the dependent voltage source. I don't know how to turn the ia into a current that can be added into the KCL equation for v2.

Thanks

 

Hi WBahn, i was wondering, do you know how to deal with the dependent voltage source. I don't know how to turn the ia into a current that can be added into the KCL equation for v2.

Thanks

What if it were just a regular old voltage source with a value of Vfred? You'd declare the node voltage V2 to be equal to -Vfred and be done with that node equation, right? Well, instead of it having a value of Vfred, it has a value of 20V/A*ia. So declare the node voltage V2 according and move on.

Please take everything you've learned thus far and write your nodal equations from scratch (and post them). Then we can talk more.

 

But it is NOT a current source. It is a current-controlled voltage source (CCVS). Through some means, it senses the current ia. It then programs the voltage source to deliver 20V, positive at the bottom relative to the top, for each amp of current that is flowing in ia in the direction indicated.

Thank you for your 'correction'.

If you read through the thread you will see that we have been there, done that and resolved the matter.

You will also see that once the nature of the dependent source had been established beyond doubt I recommended introducing voltage equations.


@Tesla
I asked if you could think of some voltage equations because there are many ways to solve this, and I wanted to find out which method your lecturer teaches.

I am guessing he teaches supernodes so here is a model solution to follow, based on supernodes and KVL.

Note carefully the lecturer here labels the branch current directions current as I said.


http://www.youtube.com/watch?v=bPqXrUQOsNo

Have you covered the double suffix notation for the above method?

 

Thank you for your 'correction'.

If you read through the thread you will see that we have been there, done that and resolved the matter.

You will also see that once the nature of the dependent source had been established beyond doubt I recommended introducing voltage equations.

Yeah. At the time I posted I thought I was looking at the last post in the thread. Turns out there was another page that I didn't realize was there.