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I am trying to solve for the circuit that I have attached.

So I know that for a opamp, it does not draw any currents into its input side and the nodes b and c are the same potential. To figure out the potential at node b, i need to know I_6, but that 6k resistor is messing everything up.

If I assume that the 6k resistor is parallel to other 6k resistors then I can solve for I_6=1 mA

However, if that is the case then I_12=1 mA as well. But that means that the resulting voltage at node d is 0...which does not make sense..

Furthermore, from node c, I can use that to solve for the potential at node d.

I cannot say all three 6k resistors are in series since from that diagram it does not seem to be unless the ground has to do something with it.

Am I missing something here?

Here is my math:

V_a=12V

I_6=12V/12k = 1mA

therefore: V_b=V_c=6V

I_3=(V_c-3V)/3k = 1mA

V_d=V_c+9I_3=6+9=15V

this does not make sense since from V_a, I_12=1mA and that would result in V_d=0V...

DM

P.S sorry the diagram is so small!

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# Homework Help: Solving a DC Circuit with OpAmp

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