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photo diode

Discussion in 'General Electronics Discussion' started by PRIYADHARSHINI, Sep 18, 2014.

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  1. PRIYADHARSHINI

    PRIYADHARSHINI

    137
    8
    Feb 6, 2014
    hi
    i want to design the linear signal conditioning unit for photo diode...the maximum output of the photo diode is 2.35V.
    i have designed the circuit with filter and amplifier with gain 2.083. where it can produce 5v for 2.35v.i want to give this to ADC

    here i have uploaded my schematic.can anyone suggest me this circuit is good or any other ways to design a signal conditioning unit
    1.may i use instrumentation amplifier .will it provide linear output?
     

    Attached Files:

  2. Harald Kapp

    Harald Kapp Moderator Moderator

    11,266
    2,577
    Nov 17, 2011
    That's not the way to design a photodiode receiver (amplifier).
    Firstly a photodiode normally is not used as a voltage source but as a current source.
    Secondly, R3 is much too small and will overload the diode.

    Read this article on how to design a photodiode amplifier.
     
    PRIYADHARSHINI and KrisBlueNZ like this.
  3. PRIYADHARSHINI

    PRIYADHARSHINI

    137
    8
    Feb 6, 2014
    thank u.so first i have to convert that current (which can be produced by the photo diode) into voltage
    is it right?
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    11,266
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    Nov 17, 2011
    this is what the photodiode amplifier in the linked reference does.
     
  5. PRIYADHARSHINI

    PRIYADHARSHINI

    137
    8
    Feb 6, 2014
    for this first we want to know the how much the current can be produced by the photo diode for the incident light
    then from max and min current we have to calculate the Rf which will produce max 5v
     
  6. Harald Kapp

    Harald Kapp Moderator Moderator

    11,266
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    Nov 17, 2011
    You'll find this figure in the datasheet of the photodiode.
     
  7. PRIYADHARSHINI

    PRIYADHARSHINI

    137
    8
    Feb 6, 2014
    yes.but is this the procedure to design the transimpedance amplifier?
     
  8. Harald Kapp

    Harald Kapp Moderator Moderator

    11,266
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    Nov 17, 2011
    I should think so. How else would you go about it?
     
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