Summing op amp circuit help?

  • #1
45
5

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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Answers and Replies

  • #2
686
172
I think you must have a math error somewhere. Are all the signs correct?
 
  • #3
45
5
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
 
  • #4
686
172
Can you post it?
 
  • #6
686
172
Check the polarity on the 4.5.
 
  • #7
45
5
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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