Op-Amp Output Voltage Calculation with Two Input Voltages

  • Thread starter Thread starter mad_monkey_j
  • Start date Start date
  • Tags Tags
    Op-amp
Click For Summary

Homework Help Overview

The discussion revolves around deriving the output voltage expression for an operational amplifier (op-amp) circuit with two input voltages, V1 and V2. Participants are exploring the relationships between the input voltages and the output voltage in the context of an inverting amplifier configuration.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to understand how to derive the output voltage based on two input voltages. Questions are raised about the expected voltage at the negative input terminal and the current flowing into it. There is also discussion about the currents through the resistors associated with each input voltage.

Discussion Status

The discussion is progressing with participants sharing their thoughts on the relationships between the input voltages and the output voltage. Some have proposed expressions for the output voltage based on their understanding of the circuit. There appears to be a collaborative effort to clarify concepts and confirm reasoning.

Contextual Notes

Participants are working under the constraints of deriving an expression without complete information about the circuit configuration, as an image was mentioned but not provided in the text. There is an emphasis on understanding the behavior of the op-amp with two inputs.

mad_monkey_j
Messages
33
Reaction score
0

Homework Statement



Derive the expression for the output Vo in terms of the input voltages V1 and V2?
Attached image is the cir

Homework Equations


Inverting amp:
A=Vo/Vi=-Rf/Ri
Vout=-Rf/I_2


The Attempt at a Solution


No idea how to go about this question with two input voltages.
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    6.7 KB · Views: 511
Physics news on Phys.org
If there was only one input voltage (and input resistor), what voltage would you expect to see at the - input of the op-amp? What current flows into the - input terminal of the op-amp?
 
The current across R1
V1/10k
The current across R2
V2/5k

So I1 is V1/10k +V2/5k?
 
Okay. Presuming that you understand why this is so, can you proceed to state the expected output voltage as a function of the inputs?
 
so Vout = -Rf*(V1/10k +V2/5k)?
 
You sound surprised. Yes, that is the logical consequence, is it not?
 
yea didn't think it would be that simple tbh, i was thinkin it would be huge although i didn't know where to start either.
 

Similar threads

Operational Amplifiers & Resistors to form a Black Box
  • · Replies 10 ·
Replies
10
Views
2K
Calculating Input Voltage for Switched Op-Amp Circuit
  • · Replies 7 ·
Replies
7
Views
2K
Engineering Why is the voltage source high potential into node 1 at -12 V in this op amp problem?
  • · Replies 15 ·
Replies
15
Views
3K
Engineering Calculating the unknown voltages in ideal op-amp circuits
  • · Replies 13 ·
Replies
13
Views
3K
How does a buffer amp not remove all loading effect?
  • · Replies 1 ·
Replies
1
Views
2K
Engineering Op amp circuit -- Did I calculate the output voltage correctly?
  • · Replies 12 ·
Replies
12
Views
4K
What are the values of Rf and V2 for the given circuit?
  • · Replies 3 ·
Replies
3
Views
2K
How Can You Maximize Gain in Ideal Op-Amps?
  • · Replies 22 ·
Replies
22
Views
3K
Any advice to make this Op-Amp temperature controller circuit work?
  • · Replies 34 ·
2
Replies
34
Views
4K
Question about bistable multivibrator op amps
  • · Replies 2 ·
Replies
2
Views
3K