Problem with simulation in proteus???

Thread Starter

Generation

Joined Apr 4, 2020
11
I built the circuit for simulating the all-pass filter by using optocouplers. But I don't know why its frequency response differs so much from the same but with the resistors instead of the optocouplers.
 

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JohnInTX

Joined Jun 26, 2012
4,007
Welcome to AAC!
A quick scan of your .zip file shows no problems but you should know that most members, including me, will NOT open a .zip file due to security concerns. Please post files in their native format.
Good luck!
 

Thread Starter

Generation

Joined Apr 4, 2020
11
Welcome to AAC!
A quick scan of your .zip file shows no problems but you should know that most members, including me, will NOT open a .zip file due to security concerns. Please post files in their native format.
Good luck!
I can't post it, because file's format is unallowed here. So I can post images:
Img.1 - two circuits(the higher one is the circuit we want to work as an all-pass filter, the bottom one is with resistors instead of optocouplers)
Img1.jpg
Img.1 - two circuits(the higher one is the circuit we want to work as an all-pass filter, the bottom one is with resistors instead of optocouplers)

Img2.jpgImg.2 - the frequency response of the circuit with the resistors and the response which we like

Img3.jpgImg.3 - the frequency response of the circuit with optocouplers instead of the resistors. In theory it shouldlook exactly like the Img.2
Img4.jpgImg.4 - the characteristics of the operational amplifiers I use. I thought it might be the reason for this difference, I know it's not right but still.

If I must post something else, please tell me. I'll do it.
 

bertus

Joined Apr 5, 2008
20,442
Hello,

The PC817 optocoupler will not create a linear resistor.
Better use an optocoupler with a fet as output, like the H11F1.

Bertus
 

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Thread Starter

Generation

Joined Apr 4, 2020
11
Hello,

The PC817 optocoupler will not create a linear resistor.
Better use an optocoupler with a fet as output, like the H11F1.

Bertus
What if I don't have H11F1 in Proteus, can I interchange it with some another linear optocoupler? Or can I download a package for Proteus with it?
 
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