Current to voltage converter

Discussion in 'The Projects Forum' started by Dheeraj123, Feb 7, 2016.

  1. Dheeraj123

    Thread Starter New Member

    Feb 7, 2016
    4
    0
    Hi all,
    I need to convert i to v using photodiode and iv converter, now the photodiode can give reverse light current upto micro amps and to convert it to volt i am using opamp with has max input bias current of about nano amps , now how can i convert this micro amps to nano amps because it should not destroy my opamp , can u please suggest a current limiter circuit so that my voltage remains the same

    Anyone ,? Please
     
    Last edited by a moderator: Feb 7, 2016
  2. bertus

    Administrator

    Apr 5, 2008
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  3. Dheeraj123

    Thread Starter New Member

    Feb 7, 2016
    4
    0
    Thanks sir, went thro the transimpedance amplfr design but the basic question still remains that if i supply opamp with micro amps andif it has ratings of nano amps then will it take only what it needs i. e. Nano or will it take micro amps?
     
  4. Sonoran Desert Tortoise

    Member

    Oct 30, 2014
    53
    34
    What are you trying to do? Is your photodiode part of a sensor set-up or something else?

    Show your schematic (of your photodiode circuit) and what you want to measure.. And why.

    Then we can help you.
     
  5. Dheeraj123

    Thread Starter New Member

    Feb 7, 2016
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    0
    Please find the ckt attached, i am using laser and photodiode in my project but ldr and torch in the circuit,
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Sorry, but I do not see any attachment.
    You can upload a file using the "Upload a File" button below the reply windows.
    The file may be a JPG, PNG or PDF. (some more formats are given in the dialog pop-up).

    Bertus
     
  7. Dheeraj123

    Thread Starter New Member

    Feb 7, 2016
    4
    0
    Oh.. Sorrry sir, Thanks all i got that right..
    Thank you all
     
  8. crutschow

    Expert

    Mar 14, 2008
    13,052
    3,244
    The input bias current is a necessary but unwanted current that the op amp requires for its internal operation. It has nothing to do with the input current you want to detect (other than creating a small offset bias at the output).
    The voltage out versus the current in is determined by the value of the feedback resistor you use (Vout = In * Rfdbk).
     
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