Greetings all -
First time poster here and I am very very rusty at Circuit theory. I am trying to get back into it, but am getting very frustrated at the same time. What may have been simple many years ago is just not clicking with me anymore.
I am working through problems in a Schaum's guide. I have attached the problem (diagram, Figure 3-27). They do provide the answer but not the steps. I am trying to find V_ab.
For this particular problem the answer is 20V. However, V_ab is in the middle of this circuit. The total resistance is 10 ohms, and the total voltage (I believe) is -35V (-20 +25 - 15 - 10), which would lead to a current of -3.5A. If signs didn't matter, then the total voltage would be 70V, and the current would be 7A. So that's my first clarification - which one is correct?
As for V_ab - the way I understand it is the V_ab is the voltage drop from node a to node b, which is the same of the voltage drops across the components connected between nodes a and b either to the right or left of node a.
I assume that we are doing KVL in some sense, where the sum of all voltages in a loop must equal zero. While I am not clear here either, and in doing both right and left loops with both -3.5 A and 7A, I do not get 20V for V_ab.
I am trying to understand where I am going wrong so I can get better at this. Any guidance would be helpful.
Thanks!
10th
Mod: Added clip from PDF.
First time poster here and I am very very rusty at Circuit theory. I am trying to get back into it, but am getting very frustrated at the same time. What may have been simple many years ago is just not clicking with me anymore.
I am working through problems in a Schaum's guide. I have attached the problem (diagram, Figure 3-27). They do provide the answer but not the steps. I am trying to find V_ab.
For this particular problem the answer is 20V. However, V_ab is in the middle of this circuit. The total resistance is 10 ohms, and the total voltage (I believe) is -35V (-20 +25 - 15 - 10), which would lead to a current of -3.5A. If signs didn't matter, then the total voltage would be 70V, and the current would be 7A. So that's my first clarification - which one is correct?
As for V_ab - the way I understand it is the V_ab is the voltage drop from node a to node b, which is the same of the voltage drops across the components connected between nodes a and b either to the right or left of node a.
I assume that we are doing KVL in some sense, where the sum of all voltages in a loop must equal zero. While I am not clear here either, and in doing both right and left loops with both -3.5 A and 7A, I do not get 20V for V_ab.
I am trying to understand where I am going wrong so I can get better at this. Any guidance would be helpful.
Thanks!
10th
Mod: Added clip from PDF.
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