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Good comparator IC for LDR light sensor circuit?

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by hoghunter, Aug 15, 2017.

  1. hoghunter

    hoghunter Member

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    Location:
    Texas
    I will be using this circuit for the light sensor portion of several projects. What IC would you recommended for this application.
    Power supply will be 7.4v, 9v & 12v for various applications. Thanks.

    upload_2017-8-15_18-54-49.png
     
  2. flatfootskier

    flatfootskier Member

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    I'd think any op amp would do. Without any feedback though I'd expect it to repeatedly switch when sat at the threshold.

    I think VCC/Ground/Output area bit swapped around
     
  3. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi hh,
    The LM393 requires hysteresis, else the output could oscillate close to the switch over from day/nite.
    Also how do you plan to set the lite/dark switch over for different environments/LDR's
    The LM393 output is open collector, you need a pull up resistor to +v.
    Add some decoupling caps across the power rails.

    Wasting power with two 1k's across the supply, 10k's would be better.
    I agree with 'ff',tidy up the polarity layout of the circuit
    E
     
  4. dave

    Dave New Member

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  5. jjw

    jjw Member

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    TEMT6000 is not a LDR, it is a NPN photo transistor.
    Absolute maximum collector-emitter voltage is 6V.
    Datasheet:
    https://www.google.fi/url?sa=t&sour...ggeMAA&usg=AFQjCNEMFKBz8o3gbYgnW-UMxmvfeKcvaQ
     

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