Operational Amplifiers

Discussion in 'Electronics Homework Help' started by vasimavr, Sep 4, 2014.

1. vasimavr

8
0
Sep 4, 2014
Hi I am Vasimavr and I was wondering if you could help me do my homework.

For the circuit of the picture, calculate the output V0.

R1 = 10 Kohm
R2 = 10 Kohm
R3 = 20 Kohm
R4 = 10 Kohm
R5 = 50 Kohm

V1 = 4V
V2 = 3V
V3 = 6V

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Last edited: Sep 4, 2014

5,164
1,081
Dec 18, 2013
You missed something from your post.
"Hi I am Vasimavr and I was wondering if you could help me do my homework"
"Vasimavr"

3. vasimavr

8
0
Sep 4, 2014
You have right sorryyy

5,164
1,081
Dec 18, 2013
We can help but we won't do it for you. Tell us what you understand and what have you tried. Do this for all your posts.

5. davennModerator

13,672
1,891
Sep 5, 2009
Hi Vasimavr

as I have said in your 2 other posts ......

Ok, so you must have been studying this subject in class
What have you learnt so far about biasing transistors in general ?
what formula do you think are appropriate to help you solve this question ?

cheers
Dave

6. KrisBlueNZSadly passed away in 2015

8,393
1,270
Nov 28, 2011
There's a problem with that question. Look at V3. It's connected to the summing node at the inverting input of the first op-amp. The non-inverting input is connected to 0V. If that op-amp was operating (pun intended) normally, the inverting input would also be at 0V. But the question specifies that V3 is +6V. If +6V is fed into that point, that will cause that op-amp's output to swing hard to positive, and the voltage won't be defined, because the power supply rails and the op-amp type aren't specified.

That would probably cause the second op-amp to do the same thing. So the circuit's output would be some undefined positive voltage somewhat less than the positive supply rail.

Perhaps that diagram is for a different question?

7. vasimavr

8
0
Sep 4, 2014
Thanks for reply. It is the correct exercise diagram... I have solve a same exercise but in this case i cannot take correct results...

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8. KrisBlueNZSadly passed away in 2015

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1,270
Nov 28, 2011
The schematic in post #7 is different from the one at the start of this thread.

If you exchange all of the inputs on your schematic in post #7 (you have them reversed), then it's probably easy enough to solve it. (I haven't tried.) But the schematic in post #1 is different. It has a voltage, V3, connected directly to the summing node of the first op-amp. This is not valid.