What is this unique op-amp's name and how do I find Vout?

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Homework Help Overview

The discussion revolves around a unique operational amplifier circuit where the input voltage is connected to both the inverting and non-inverting terminals. Participants are tasked with finding the output voltage (Vout) and identifying the type of op-amp used in the circuit.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • Participants express confusion about the circuit configuration, noting that it appears unconventional. Some attempt to redraw the circuit for clarity, while others question the assumptions regarding the relationships between voltages in the circuit. There are discussions about the application of Kirchhoff's laws and nodal analysis to derive Vout.

Discussion Status

The conversation is ongoing, with various interpretations being explored. Some participants have offered insights into the circuit's behavior, while others are seeking further clarification on specific points, such as the logic behind the output voltage being a division of the input voltage.

Contextual Notes

Participants mention the supply voltages of ±10V and discuss the implications of component tolerances on the circuit's performance. There is also a reference to the complexity of the circuit as more of an academic exercise rather than a practical application.

  • #61
gneill said:
From the original circuit diagram in the first post of the thread, Vout is tied to the (-) input of the op-amp (the node labeled b). Assuming an ideal op-amp, the (+) input must be at the same potential. Thus node a is also at Vout potential. Between node a and ground is R4. Thus VR4 must be equal to Vout.

Ahhh...I see that now. Thanks for pointing that out...and good catch! I guess you need an electronics whiz vision for that :)

I was originally trying to search an old thread for an info about op-amps I was once provided about the difference between V- and V+

Speaking of ideal op-amps,

In comparators, or order for them to work, we get different value for V+ and V-

In non-comparators op-amps, V- always equal V+?

I remember that answer being written to me in the past but I can't find the thread :(
 
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  • #62
Femme_physics said:
Speaking of ideal op-amps,

In comparators, or order for them to work, we get different value for V+ and V-

In non-comparators op-amps, V- always equal V+?

That's the basic rule of thumb. Usually you can tell when an op-amp is being used as a comparator because you won't find any feedback path going from Vout to the V- input.
 
  • #63
Perfect. Gneill, you are a world of help.. Thank u very much
 
  • #64
Femme_physics said:
Perfect. Gneill, you are a world of help.. Thank u very much

Glad to help :smile:
 

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