)Transient-voltage-suppression diode vs SIDAC

Discussion in 'General Electronics Chat' started by minh, Oct 27, 2014.

  1. minh

    Thread Starter Member

    Nov 24, 2010
    24
    1
    Dear all
    Please help me to know what is different:
    Transient-voltage-suppression diode and Sidac ???
    Can I use P6KE120ca (TVS) replacementMK1V125 =K1200 (Sidac) in this circuit. please see photo .Thank you so much.

     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    the tvs is essentially a high current zener. there is no action like a diac with a zener. the diac or sidac has a diferent voltage for conducting and turning off, that makes it oscilate. the zener just goes to a voltage and conducts.
     
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  3. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,129
    266
    The SIDAC will breakdown and conduct heavily until a much lower voltage / current threshold is reached.

    Kind of like 'snap-action'
     
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  4. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
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    but thats not what it takes to oscilate, there has to be a difference between turn on and turn off, kind of liie a neon bulb, turns on at a higher voltage than it turns off as in "relaxation oscilator".
     
  5. minh

    Thread Starter Member

    Nov 24, 2010
    24
    1
    Dear alfacliff and Sensacell
    Thank you so much for your time helpful me.
    Kind regards
    minh
     
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  6. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,129
    266
    I think it's properties are very similar to a neon lamp, the OP's circuit is a relaxation oscillator, it's a repeating strobe light circuit.
     
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