Here's a derivation already done.
op amp - Feedback loop-gain(beta) derivation for the inverting amplifier? - Electrical Engineering Stack Exchange
I see nothing wrong with the question, to me it's clearly an inverting circuit. Am I missing something? The gain is negative so there is a typo there, is that what you mean?
Well I'm glad you guys see that. I saw it as Vin to ground...and ground feeding the + side of the op amp.
We have Vout at the output terminal. Why is Vin next to the ground terminal farther away but not next to the series resistance terminal?
In any textbook I've never seen this nor in any National Semi or Analog Devices ANs, Data Sheets, etc. Anything I've ever seen has Vin next to the input terminal.
We have Vout at the output terminal. Why is Vin next to the ground terminal farther away but not next to the series resistance terminal?
In any textbook I've never seen this nor in any National Semi or Analog Devices ANs, Data Sheets, etc. Anything I've ever seen has Vin next to the input terminal.
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That was just sloppy writing, you can't ground a voltage source that is already referred to ground, that would short it out.
I looked at that Ray, thanks. It didn't help me understand it. I have no idea how to come up with k. In the problem, I calculated Beta given the information and formulae I had at the time. Thanks for your effort. I'm missing some big picture item.
It is what it is. I get burned from sloppy writing and graphics, diagrams etc. #8 should be thrown out then based on the proper answer not shown.
It is what it is. I get burned from sloppy writing and graphics, diagrams etc. #8 should be thrown out then based on the proper answer not shown.
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Ideal Op-amp Characteristics
The first couple adages were what I remember getting hammered into my head early to start our analyses before we expanded it to "well, lets talk about non-ideal opamps"
Then you can do a mesh/nodal analysis from those basics.
The first couple adages were what I remember getting hammered into my head early to start our analyses before we expanded it to "well, lets talk about non-ideal opamps"
Then you can do a mesh/nodal analysis from those basics.
and the other details ---- block diagram equations and the circuit equations --
op amp - What is noise gain, really? And how is it determined in the general case? - Electrical Engineering Stack Exchange
THx-RNMarsh
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Sync, don't think so much and try to answer the questions as they were meant. This is 'almost obviously' an inverting circuit and Vin is in the right place, BUT the subscript confused you to think it was driving the ground, a simple mistake, because you are a student and haven't seen thousands of circuits typed, printed or even scribbled in every which way. It is best to try to answer the questions in the way that the test was really meant to ask you, and not fight with the instructor.
The + sign on an op-amp symbol doesn't designate the "correct" input of an op-amp, when an op-amp is wired to act as an inverter then, in general, the - pin becomes the "input".
Also, "negative gain" is a misnomer, gain is only a quantitavie number telling what the gain is, irrespective of the phase.
https://www.electronics-tutorials.ws/opamp/opamp_2.html
Inverting op-amp (video) | Amplifiers |
Khan Academy
🙂
Also, "negative gain" is a misnomer, gain is only a quantitavie number telling what the gain is, irrespective of the phase.
https://www.electronics-tutorials.ws/opamp/opamp_2.html
Inverting op-amp (video) | Amplifiers |
Khan Academy
🙂
Hmm, I don't know if I would call it a misnomer, voltage gain is Vout/Vin. Almost every op-amp datasheet also will describe it with a negative number when the circuit described is inverting.
Your point is understood though.
The other major clue is that the resistor in position Ri is labeled as Ri (Rin). Most non-inverting circuits in textbooks label them R1 and R2 that I have seen.
double hmm... how about, there is no negative gain, BUT... more correctly we ought to plug in the imaginary number jomega 180 degree (ie. an inverting amp), in such case if we would use, say A = -50, that wouldn't work, would it?
ugh, my math is rusty. 😱
ugh, my math is rusty. 😱
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I think I know the preamp;-)
So, we have a preamp witch works in two configurations, *with the same components*.
If I remember well, the distortions were low enough in both modes to can exclude any difference to come from there. Despite this, a lot of people tend to make the difference and have a preference. And I tend to believe there is really a difference in the presentation..
Now the question is; why ?
The only answer I can imagine is : Dynamic behavior.
I did look around the net and it seems there are two interpretations of "negative gain", one group thinks it is an attenuation, the other not but still maintain the "negative gain" notion.
The confusing part is the added - sign to the gain figure, if I type in 20log(-50) on my pocket calculator that would render an error, G=50 on the other hand compiles into around 34dB, but we can't just add a - sign to this figure afterwards either, otherwise it would mean something different, ie. attenuation.
Trivial stuff that makes one confused. 🙂
The confusing part is the added - sign to the gain figure, if I type in 20log(-50) on my pocket calculator that would render an error, G=50 on the other hand compiles into around 34dB, but we can't just add a - sign to this figure afterwards either, otherwise it would mean something different, ie. attenuation.
Trivial stuff that makes one confused. 🙂
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Stereophile has posted up the measurements of that $93k amp that has 'designed distortion' he was mentioning Ypsilon Electronics Hyperion monoblock power amplifier Measurements | Stereophile.com. Whilst I have seen worse, that's pretty shocking performance for the money.
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