Operational amplifier with feedback problem

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The discussion revolves around a problem with calculating the feedback factor beta in an operational amplifier circuit, where the expected value is 0.4926 V/A. Participants clarify that the op-amp's output resistance (ro) should be modeled in series with the controlled voltage source. It is confirmed that when a resistance is placed in parallel with an ideal voltage source, the Thévenin equivalent resistance remains zero. The conversation emphasizes the importance of correctly applying circuit rules, particularly regarding the behavior of voltage sources and their effect on parallel resistances. The user plans to reattempt the question with this new understanding.
TheRedDevil18
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Homework Statement


upload_2016-11-23_22-8-8.png


Homework Equations

The Attempt at a Solution


IMG_20161123_220433.jpg

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Using the equations above, I'm not getting the right answer for beta which is 0.4926 V/A.
Is my model wrong ?
 
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The op-amp's ro should be shown in series with the controlled voltage source.
 
NascentOxygen said:
The op-amp's ro should be shown in series with the controlled voltage source.
So with a voltage source, ro is always in series ?
 
TheRedDevil18 said:
So with a voltage source, ro is always in series ?
Yes.

If you were to place a resistance in parallel with an ideal voltage source, what would be the Thévenin equivalent resistance of that combination?
 
NascentOxygen said:
Yes.

If you were to place a resistance in parallel with an ideal voltage source, what would be the Thévenin equivalent resistance of that combination?

Would it be a voltage source in series with the resistance ?, I know that a current source with a parallel resistance is equal to a voltage source in series with that resistance
 
TheRedDevil18 said:
Would it be a voltage source in series with the resistance ?
Guessing is not allowed.

Can you determine it?
 
NascentOxygen said:
Guessing is not allowed.

Can you determine it?

Would it be zero ?, I determined it by using the rules. When you have a voltage source you short it and remove the load, so that means all the current will flow through the short and not through the parallel resistor
 
TheRedDevil18 said:
Would it be zero ?, I determined it by using the rules. When you have a voltage source you short it and remove the load, so that means all the current will flow through the short and not through the parallel resistor
Right. A resistance has no effect if you erroneously add it parallel to an ideal voltage source: the effective source resistance here would stay as zero.
 
NascentOxygen said:
Right. A resistance has no effect if you erroneously add it parallel to an ideal voltage source: the effective source resistance here would stay as zero.

Ok, thanks, I'll attempt the question again
 

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