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VinnyCee
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Homework Statement
Find the Thevenin equivalent at terminals a-b in the circuit below.
http://img361.imageshack.us/img361/2250/chapter5problem36gq0.jpg
Homework Equations
KVL, KCL, v = i R, current and voltage equations for Operation Amplifier
The Attempt at a Solution
So I altered the diagram a bit.
http://img258.imageshack.us/img258/4382/chapter5problem36part2pr4.jpg
[tex]I_1\,=\,\frac{V_S}{R_1}[/tex]
[tex]I_2\,=\,\frac{V_S\,-\,V_1}{R_2}[/tex]
KCL at [itex]V_S[/itex])
[tex]I_1\,=\,-I_2\,\,\longrightarrow\,\,\frac{V_S}{R_1}\,=\,-\frac{V_S\,-\,V_1}{R_2}[/tex]
[tex]V_1\,=\,\frac{R_2\,V_S}{R_1}\,+\,V_S[/tex]
[tex]V_{Th}\,=\,V_1\,=\,\frac{R_2\,V_S}{R_1}\,+\,V_S[/tex]
Is that right? If so, I will now put a test current of 1 Amp at the terminals to get the [itex]R_{Th}[/itex].
[tex]I_2\,=\,1[/tex]
[tex]\frac{V_S\,-\,V_1}{R_2}\,=\,1\,\,\longrightarrow\,\,V_1\,=\,V_S\,-\,R_2[/tex]
Now, using v = i R to get the Thevenin equivalent resistance.
[tex]R_{Th}\,=\,\frac{V_1}{1}\,=\,V_S\,-\,R_2[/tex]
Does that seem correct?
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