Amplifier with adjustiable output impedence

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drahte1905

New Member

• Jan 7, 2008

• #1

Design an amplifier that has adjustable output impedance and the range of impedance should be 1K<ri<10K. Voltage gain of the amplifier should be set to 5.

Use an Operational Amplifier, a JFET or a BJT and peripheral passive components to realize the Project.

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I have got several concepts in my mind but when I simulate them they all failed

And I can't find a way to build this kind of a circuit

Any of you know a concept about this circuit

It is a midterm project and has got due date at 09.01.08 so I am in a little bit a rush

 

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on1aag

New Member

• Jan 7, 2008

• #2

Hi lazy devil,

Do you really think we will do all your homework ?
However, look at this circuit:

https://www.electro-tech-online.com/threads/wien-bridge-vs-psipce-mad-student.35176/

The amplifier has a non-inverting gain of 3,2.

on1aag.

 

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drahte1905

New Member

• Jan 7, 2008

• #3

Thanks for reply

But I have stuck with these projects and my finals are too close also these are maybe 2 of 14 projects

I can't have exact answers to my questions this is why I am writing here

I really put considerable effort on these projects, I didn't ask for pre-made projects, I am just asking for help

It is easier to help rather than just talking...

 

K

kchriste

New Member

Forum Supporter

• Jan 7, 2008

• #4

Maybe a pot in series with the output to vary the impedance?

 

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drahte1905

New Member

• Jan 8, 2008

• #5

I constracted a circuit but not simulated tomarrow I will simulate and also constract it in labratory

It is very basic non-inverting amplifier with gain for this I will use 100k and 400k as Rf and Rk so my gain gone be 5

Following I will connect 10K at one branch and parllel to this branch a pot [vary between 10k-200k] + 900ohm resistor

So when pot is off or r=0 then 1 have 0.9K ohm output resistance and when pot reach 200K ohm I will have 9.8Kohm also when pot 110K ohm I will have 9.1K[not remember exactly]

Any way I planning to simulate this circuit in following hours I will post a diagram and outputs...