Non Inverting Operational Amplifier

AI Thread Summary
The discussion focuses on deriving the gain expression Vout/Vin for a non-inverting operational amplifier with a capacitor in series with R1. The initial expression for gain is given as 1 + R2/[R1 + 1/(jwC)], which needs to be converted into the form A + jB. The user struggles with this conversion but eventually rewrites the gain as 1 + R2/[R1 - j/wC]. Guidance is provided on multiplying by the conjugate to simplify the expression, leading to a successful resolution of the problem. The user confirms that they have solved the issue after applying the suggested method.
theuniverse
Messages
53
Reaction score
0

Homework Statement


Derive an expression for the gain Vout/Vin. Express your answer in the form of A+jB.

Homework Equations



The Attempt at a Solution


If C is the capacitor in series with R1, gain = 1 + R2/[R1 + 1/(jwC)]. It says to express it in the form of A (real)+ jB (imaginary), but I'm not sure how to make the conversion from my solution of gain to the form of A+jB.
Any help is appreciated.

Edit: Figured that I can rewrite it as gain = 1 + R2/[R1 - j/wC] and I tried multiplying by the conjugate but I still can't get it...
 

Attachments

  • op amp.jpg
    op amp.jpg
    2.8 KB · Views: 441
Last edited:
Physics news on Phys.org
theuniverse said:

The Attempt at a Solution


If C is the capacitor in series with R1, gain = 1 + R2/[R1 + 1/(jwC)]. It says to express it in the form of A (real)+ jB (imaginary), but I'm not sure how to make the conversion from my solution of gain to the form of A+jB.
Any help is appreciated.

Edit: Figured that I can rewrite it as gain = 1 + R2/[R1 - j/wC]
Yes, looks good so far.
and I tried multiplying by the conjugate but I still can't get it...
Multiply by (conjugate/conjugate), where "conjugate" is the conjugate of the denominator.

For example:

\frac{c}{a+jb} = \frac{c(a-jb)}{(a+jb)(a-jb)} = etc.
 
Thanks! yea I ended up doing that by kept forgetting the extra 1 for the gain. All solved now though.
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Struggling to make relation between elastic force and height'
Hello guys this is what I tried so far. I used the UTS to calculate the force it needs when the rope tears. My idea was to make a relationship/ function that would give me the force depending on height. Yeah i couldnt find a way to solve it. I also thought about how I could use hooks law (how it was given to me in my script) with the thought of instead of having two part of a rope id have one singular rope from the middle to the top where I could find the difference in height. But the...
Back
Top