PWM -> Optocoupler -> Triac

Discussion in 'The Projects Forum' started by Konstabel, Feb 25, 2008.

  1. Konstabel

    Thread Starter Active Member

    Jan 31, 2008
    52
    0
    First I would like to thank everybody that has helped me so far and answered my questions. Hgmjr, Scubasteve, beenthere, and kender in particular.

    No to my next question.

    Will it be possible to implement the attached circuit I would like to regulate the power to the load via the PWM output from a uP.

    This lead me to another question: How does an optocoupler actually transfer the input to output? Is the output a function of the input, or just an on/of depending on the input? (Should this be asked in a separate thread?)
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    An opto-coupler (a.k.a. an opto-isolator) is composed of an LED and a companion photo-transistor all encapsulated inside the same package. This provides a circuit element that is excellent for providing galvanic isolation between the control source and load.

    While the action is linear, the opto-isolator is most often used in swithcing applications.

    There are opto-isolators that contain additional internal interface circuitry to help avoid the need to provide such circuitry external to the device.

    hgmjr
     
  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The triac turns off 100 times per second when the mains frequency is 50Hz. Then your PWM signal must be syncronized to the mains frequency so it can act like a light dimmer.
     
  4. shankarNITIAN

    New Member

    Mar 16, 2009
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    what is the use of triac in this circuit,please elaborately explain.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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  6. Storm7591

    New Member

    Apr 4, 2009
    1
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    Phase control
     
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