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zener reverse vltg

Discussion in 'General Electronics Chat' started by bublee, Oct 31, 2009.

  1. bublee

    bublee New Member

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    can anybody tell me how to obtain a higher reverse blocking capacity from lower PIV zener ........
     
  2. colin55

    colin55 Well-Known Member

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    Add zeners in series
     
  3. bublee

    bublee New Member

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    thanx for the reply
     
  4. dave

    Dave New Member

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  5. Vizier87

    Vizier87 Active Member

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    since we're on the topic of zeners... see this circuit:
    http://www.electro-tech-online.com/attachments/e-drum-preamp-png.33856/

    This circuit is proposed by audioguru for my disdrometer project
    http://www.electro-tech-online.com/threads/acoustic-disdrometer.98174/

    How does that zener clamp the output from a Piezo transducer?
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I was wrong.
    The BAT85 is a Schottky diode, not a zener diode.
    It conducts when the input goes negative by only 0.2V to avoid destruction of the input of the opamp that has a max allowed negative voltage of -0.3V.
     
  7. Vizier87

    Vizier87 Active Member

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    okay.... so a Schottky diode it is.. can it be replaced by the IN- series? Like the IN4148 or IN4001?
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The Schottky diode has the required 0.2V to 0.3V forward voltage to stop the negative input to the opamp from exceeding its max allowed negative voltage of -0.3V.

    An ordinary diode has a forward voltage of 0.6V to 0.7V so the input of the opamp will be damaged.
     
  9. yafch

    yafch New Member

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    1N400X series are general purpose diodes for AC-to-DC applictions. 1N4148 is a fast switching diode. schottky diodes are little bit different from these, because of their low forward voltage drop leading to lower levels of power loss compared to ordinary P-N junction diodes. schottky diodes are also known as surface barrier,hot carrier, or even hot electron diode. they are widely used in radio frequencies as mixer or detector,and in power applications as rectifiers where low forward voltage drop is required.

    You can try google for different types of diodes or even wikipedia can help.
     

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