Summing Op Amp Circuit Troubleshooting

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Homework Help Overview

The discussion revolves around troubleshooting a summing op amp circuit where the input voltage is specified as -5V. Participants are examining the calculations related to the output voltage, which has been reported as -3V by the original poster.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants are questioning the accuracy of the original poster's calculations and the correctness of the signs used in the equations. There are requests for clarification and verification of the calculations.

Discussion Status

Some participants have offered suggestions to check for mathematical errors and polarity issues in the calculations. There is an acknowledgment of potential mistakes, but no consensus has been reached regarding the correct output voltage.

Contextual Notes

The original poster expresses uncertainty about the correctness of the homework assignment itself, indicating a possible history of inaccuracies in the provided materials.

Jayalk97
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Homework Statement


Solving for this circuit here, where V = -5V
upload_2017-2-20_1-16-36.png

Homework Equations


upload_2017-2-20_1-16-50.png


The Attempt at a Solution


I found the equation for a summing op amp like this one, plugged everything in and ended up with -3V, which is marked wrong. I'm really at my wit's end here and the homework has been incorrect in the past so I'm not even sure this is the wrong answer, any help would be appreciated.
 

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I think you must have a math error somewhere. Are all the signs correct?
 
TomHart said:
I think you must have a math error somewhere. Are all the signs correct?
I think so, I ended up writing it out and still got 3V
 
Can you post it?
 
TomHart said:
Can you post it?
Sure
20170220_013527.jpg
 
Check the polarity on the 4.5.
 
TomHart said:
Check the polarity on the 4.5.
Oh the sneaky bastards...
I got 6 volts for it thank you for your help!
 
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