Transimpedance Amplifier

Discussion in 'Homework Help' started by matth, Jul 31, 2014.

  1. matth

    Thread Starter New Member

    Jul 31, 2014
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    I've been given a task to design three types of transimpedance amp....

    A single transistor amplifier with local feedback - This is where I'm stuck.
    The output value I'm getting from the circuit simulation isn't == Rf x Iin

    My knowledge on amplifiers is extremely narrow, so maybe this is why I'm going wrong... But I have created a common emitter amp, sampling the output feeding it across a resistor and then back into the input.

    Is this incorrect?
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Just for the sake of completeness, there should be a minus sign in front of Rf. Maybe that is the issue.
     
  3. matth

    Thread Starter New Member

    Jul 31, 2014
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    I wish it was as simple as that, the output is completely different as to what I expected


    Oscilliscope output
    [​IMG]

    Circuit
    [​IMG]

    I was under the impression that the oscilloscope should be reading 10kv instead of an offset wave with peak around 2kv and trough -2.7kv
     
  4. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    I think I see the problem. You don't need R1. And, therefore, you probably calculated wrong R2.

    Let me find some links I was reading while I was thinking about your first post.
     
  5. shteii01

    AAC Fanatic!

    Feb 19, 2010
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