ok....what's the current thru the 3 ohm resistor?

 

If we have 0 volts on the bottom of the 3 ohm resistor and 12 volts on the top.....how much current is going thru it?

 

I see where this is going. Next you're going to want to know the current in the 1 ohm resistor, then the 6 ohm resistor, then the 2 ohm resistor, and the voltages at each end of those resistors--does it never end?

 

It's just bean counting. One bean at a time. But we need to count before we learn to multiply.

 

Hi,

Well if the student does not know how to proceed sometimes more information has to be given.
I was thinking of giving a range of values, like say "the result at node 21 is between 10 and 11 volts" and then the student would have something to compare.
But i was asking for the way the student had done this in the past but didnt seem to get an answer.

 

Maybe something clicked and he solved it and left. Or maybe he got tied of my questions and saw no sense in it.
Or maybe he went to sleep like I didn't.

 

Can you guys calculate the answers for me so that I can check if my calculations are right?
So far I have got Vo in 07 is 60v.

Thank you.

Hello again,

The maximum voltage in figure 07 is less than 14v. That means 60v is way too high.

Can you solve this if we make both sources constant? That is, the source to the left is 10ma constant already, and make the right source 40ma just to quote some constant current. Can you solve it then?
That can get you started.

I might add that this circuit is just a little tricky but if we use straight forward nodal analysis we can arrive at a result. I also solved it another way but it is tricky because the two current sources interact with one being dependent partly on what it itself is putting out.

 

Sorry for the late reply, I had a class to attend.

4A through the 3ohm resistor. Right?

 

I think he just wanted someone to give him the answers to pass the test. I think he needs to go back over his school maths and science notes and re read his text books. (I am assuming schools still teach in a similar way to the way I was tought over 50 years ago.)

Les.

 

I think he just wanted someone to give him the answers to pass the test. I think he needs to go back over his school maths and science notes and re read his text books. (I am assuming schools still teach in a similar way to the way I was tought over 50 years ago.)

Les.

Yes, I want the answers but I would also like to learn how to solve this kinds of problems.

 

Sorry for the late reply, I had a class to attend.

4A through the 3ohm resistor. Right?

So if I8 is 2A and I6 is 4A, how much is I4? Knowing I4, what is the voltage at node B?

 

8V at B?

So I5 is 2/3A, am I right?

 

8V at B?

So I5 is 2/3A, am I right?

No, voltage at B is not 8 volts. How much is I4? Knowing I4, what is the voltage across the 1 ohm resistor? Pay attention to the direction of I4.

 

I4 = 6A
Voltage at B = 6V

 

You haven't paid attention to the sign. Which way is the (conventional current) flowing in the 1 ohm resistor? Up or down?

 

down. So should it be -4A?

 

down. So should it be -4A?

If I8 is 2A and I6 is 4A, both down, then how much is I4?

 

oh, sorry my bad, -6A

 

The arrow shows I4 as going down, but is that really its direction?

 

No.