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

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The discussion centers on identifying a unique op-amp configuration and calculating its output voltage (Vout). Participants note that the circuit features Vin connected to both the positive and negative inputs, which is uncommon and leads to confusion about its operation. The consensus is that Vout can be determined as Vout = Vin/4, using nodal analysis and Ohm's law, despite the circuit's unusual feedback arrangement. There is also a discussion about the practical applications of such a configuration, with some participants suggesting it serves more as an academic exercise than a real-world application. Overall, the conversation highlights the complexities of analyzing non-standard op-amp circuits while encouraging the use of fundamental electrical principles.
  • #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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