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Re: [beam] Photodiode question

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  • wilf rigter
    The black lens is a filter that is transparent to Infra Red but blocks most visible light. That makes the black photodiode respond strongly to light
    Message 1 of 3 , May 7, 2007
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      The "black" lens is a filter that is transparent to Infra Red but blocks most visible light.  That makes the "black" photodiode respond strongly to light sources that contain near infra red like IR LEDs, the sun or incandescent lamps and reject light from cool sources like fluorescent lights. For detecting far infra red sources ie body heat, you must use a PIR sensor.  Check the photo diode data sheet for the sensitivity vs wavelength curve. 
       
      wilf
       
        
      ----- Original Message -----
      Sent: Monday, May 07, 2007 7:15 PM
      Subject: [beam] Photodiode question

      Hi.
      What is the difeance/advantage/ disadvantige( if any) between a Black
      photodiode and a clear one?
      I've looked up photoresistors, LRDs,CDS, and the like and read alot,
      but have not found an answer. please some one with first hand knowlage
      of this, can you help?
      Is one more light sensitive then the other?
      thanks.
      jabmechtech

    • jabmechtech
      ... blocks most visible light. That makes the black photodiode respond strongly to light sources that contain near infra red like IR LEDs, the sun or
      Message 2 of 3 , May 8, 2007
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        --- In beam@yahoogroups.com, "wilf rigter" <wrigter@...> wrote:
        >
        > The "black" lens is a filter that is transparent to Infra Red but
        blocks most visible light. That makes the "black" photodiode respond
        strongly to light sources that contain near infra red like IR LEDs,
        the sun or incandescent lamps and reject light from cool sources like
        fluorescent lights. For detecting far infra red sources ie body heat,
        you must use a PIR sensor. Check the photo diode data sheet for the
        sensitivity vs wavelength curve.
        >
        > wilf
        >
        > Thank you! I appreciate the help Wilf.
        Jab
        > ----- Original Message -----
        > From: jabmechtech
        > To: beam@yahoogroups.com
        > Sent: Monday, May 07, 2007 7:15 PM
        > Subject: [beam] Photodiode question
        >
        >
        > Hi.
        > What is the difeance/advantage/disadvantige(if any) between a
        Black
        > photodiode and a clear one?
        > I've looked up photoresistors, LRDs,CDS, and the like and read
        alot,
        > but have not found an answer. please some one with first hand
        knowlage
        > of this, can you help?
        > Is one more light sensitive then the other?
        > thanks.
        > jabmechtech
        >
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