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Hadi Setiadi
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Homework Statement
Homework Equations
Can anyone help me how to find the current 3.6mA analytically?
I have tried but I didn't get any right answer.
Thanks
Hadi Setiadi said:If I used nodal anaylsis, I could get two equations, but what equation should I use for a node between 4k and 12k resistor?
Hadi Setiadi said:If I used nodal anaylsis, I could get two equations, but what equation should I use for a node between 4k and 12k resistor?
Hadi Setiadi said:Ok, thanks. I got it.
I only need two nodes, between (R1, R2, and R4) and between (R1, R3 and (-) terminal).
rude man said:No, your second unknown node is the output of the amplifier.
It should be obvious by inspection what the voltage of the second node you cite is!
aralbrec said:With nodal analysis you are solving for voltages and you already have that voltage (Vo) ...
rude man said:Taking advantage of knowledge of the voltage at the - input,
G2(v2 - Vo) + Io = G3*Vo where in general Gi = 1/Ri, i = 1,2,3 or 4 and Io = current out of op amp.
Maybe this is not what you call a "nodal equation" but it sure solves the problem ...
Oh? And what would it be?With nodal analysis you are solving for voltages and you already have that voltage (Vo) .
aralbrec said:It doesn't solve the equation, it introduces another unnecessary unknown. By introducing Io you now have to add another equation by writing KCL at the ground node.
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An ideal opamp is a theoretical electronic component that has infinite input impedance, zero output impedance, a infinite gain, and zero offset voltage. It is used in circuit analysis as a simplified model for practical opamps.
The current through an ideal opamp without a resistor can be calculated by using the formula I = (V+ - V-)/R, where V+ and V- are the input voltages of the opamp and R is the resistance of the feedback network. In an ideal opamp, R is assumed to be infinite, so the current becomes I = (V+ - V-)/∞, which is equal to 0.
The current through an ideal opamp is assumed to be 0 because an ideal opamp has infinite input impedance, meaning that it does not draw any current from the input sources. Therefore, all of the current must flow through the feedback network, making the current through the opamp itself negligible.
No, an ideal opamp is a theoretical concept and does not exist in reality. Practical opamps have limitations and imperfections that prevent them from behaving exactly like an ideal opamp.
The concept of an ideal opamp simplifies circuit analysis by providing a theoretical model that can be used to predict the behavior of practical opamps. It allows for easier calculations and enables engineers to design and analyze circuits more efficiently.