Zener questions

Discussion in 'General Electronics Chat' started by YorksireDave, Dec 9, 2010.

  1. YorksireDave

    Thread Starter New Member

    Dec 9, 2010
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    I've come across some 30v zeners in my shed (don't ask!). I need some 6.8v and wondered if I could use the ones Ihave in any way? I was thinking could they be used in series/parallel or anything or do those rules not apply to diodes? :confused:

    Also, I've come across some IN5148 diodes which through Googling I believe are Varactor diodes! Can someone enlighten as to what they are and what I might be able to use them for. :confused:

    Thanks ;)
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  3. bertus

    Administrator

    Apr 5, 2008
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  4. tyblu

    Member

    Nov 29, 2010
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    You would have to put a 30V-6.8V=23.2V potential across the zener; this can be done by either creating a negative voltage source (-23.2V) or by floating your system ground 23.3V above a reference, then using the reference directly for the zener.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    A varactor is a diode whose capacitance varies with voltage when it is back biased. It is a variable capacitor in other words, popular with autotune features in radios (among other things).
     
  6. YorksireDave

    Thread Starter New Member

    Dec 9, 2010
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    Many thanks people. As I have a 1000 of the diodes are they worth anything?
     
  7. tyblu

    Member

    Nov 29, 2010
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    Not really worth anything. Do you know what power rating they are? DigiKey marks them up to 50c/ea for singles to ~2c/ea for 10k; 'suppose you could make $10.
     
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