# Amplifier circuit using opamp LT1001

Discussion in 'Homework Help' started by sandeep.edara, Jul 24, 2014.

1. ### sandeep.edara Thread Starter New Member

Jun 6, 2014
5
0
Hello ,

We want to see an amplification stage using LT1001 opamp,we want to get an amplification of 1v for 100mv input but when we give an input of 100mv we only see an input of 25mv in the oscilloscope and when we switch on the output it's getting amplified to 185mv .We used a circuit with R1=10k to v- ,R2=100k from v- to the output and R3 from the v+ to ground.Can anyone help me ??

2. ### to3metalcan Member

Jul 20, 2014
228
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Sounds like a basic inverting gain stage, but a picture would still help! What is your input coming from? Is 10k a big enough inout impedance to keep from loading the source?

3. ### sandeep.edara Thread Starter New Member

Jun 6, 2014
5
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Ya it is basic amplifier circuit ,but I don't understand why we couldn't get a proper output but with the same circuit in a simulation software we observe the exact output. I am uploading the circuit

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4. ### to3metalcan Member

Jul 20, 2014
228
23
This stage has an input impedance of 1kohm. What is the source of your signal? Can it drive 1K without losses due to its own output impedence?

5. ### sandeep.edara Thread Starter New Member

Jun 6, 2014
5
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The input is from function generator with sine(100mv,50hz ).Should we do any modifications ,can you help me ??

6. ### to3metalcan Member

Jul 20, 2014
228
23
One step at a time...first verify that your generator is actually putting out 100mv when it's not loaded. If it is, then attach it to your circuit and check the ac voltage at the left side of R2. If your voltage is dropping, your generator can't drive 1kohm, and you need a bigger input impedance. You initially described the circuit as R1=100k and R2 = 10k...did you build that, or the circuit you attached with 10k/1k ?

7. ### sandeep.edara Thread Starter New Member

Jun 6, 2014
5
0
I need an amplifier circuit with a gain of 10 so I used 1k,10k and also tried with 10k ,100k .But I can't get a proper amplified output. If you have any better circuit suggestions can you tell me ?

8. ### sandeep.edara Thread Starter New Member

Jun 6, 2014
5
0
Can you please suggest me another solution,I checked all the possibilities I can't get the output .

9. ### MrChips Moderator

Oct 2, 2009
12,652
3,461
Maybe the opamp is bad. Have you tried another one?
Post a photo of your circuit board.

10. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,403
1,230
Are you saying your simulation worked but your prototype didn't?

Like MrChips stated, post a picture of your circuit board ... top and bottom ....

11. ### to3metalcan Member

Jul 20, 2014
228
23
Agreed...there's either a wiring error or your LT1001 is toast. 10K should be plenty of impedance.

Jul 20, 2014
228
23