How to replace zener with TVS diode

Discussion in 'General Electronics Chat' started by abuhafss, Sep 14, 2014.

  1. abuhafss

    Thread Starter Active Member

    Aug 17, 2010
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    How a TVS (150V) diode, unidirectional and bidirectional (without cathode marking) would be used in place of zeners?

    TVS.png
     
  2. crutschow

    Expert

    Mar 14, 2008
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    Generally you just replace the zeners with the TVS diode. But note that the breakdown voltage of a TVS diode may not be as accurate as that of the zeners.

    What is the purpose of the zener/TVS circuit?
     
  3. abuhafss

    Thread Starter Active Member

    Aug 17, 2010
    153
    2
    It is used in CDI to regulate HV generated by the oscillator.
    Can the bidirectional TVS be used in either way?
     
  4. #12

    Expert

    Nov 30, 2010
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    Yes. Bidirectional means, "both ways".
     
  5. abuhafss

    Thread Starter Active Member

    Aug 17, 2010
    153
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    Okay.

    I have one schematic before me which has an inverted 1N4007 with a unidirectional TVS.
    What is 1N4007 for?

    TVS 2.png
     
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    This new drawing (post #5) shows the input voltage at 200 - 250 volts AC (DC in your first post). The 1N4007 rectifies the AC to DC by blocking the negative half of the sine wave. Normally a capacitor is used with the diode to filter the half-sine wave to DC.
     
  7. abuhafss

    Thread Starter Active Member

    Aug 17, 2010
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    The first diode on the left after 200-250VAC is for rectification, that is understood.
    But, what is function of the other 1N4007 above the TVS diode?
     
  8. #12

    Expert

    Nov 30, 2010
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    What is the rest of the circuit?
    With no information about the rest of the circuit we can not read the mind of the person that designed this with 2 diodes.
     
  9. abuhafss

    Thread Starter Active Member

    Aug 17, 2010
    153
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    I am extremely sorry, I was mistaken reading the schematic.
    Kindly ignore my post at # 5.

    And thanks all for the input.
     
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