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Zener Diode Series #

Discussion in 'General Electronics Chat' started by redart, May 3, 2006.

  1. redart

    redart New Member

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    Can anyone explain what the series numbers of zener diodes are about?.
    e.g. what's the difference between the BZX79 series and the BZX85 series ?
    Can I use an 85 in place of a 79 ?. Thanks.
     
  2. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Have you never heard of google or search engines?.

    A BZX79 is 500mW and a BZX85 is 1.3W.
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The details on the datasheets show that the two zener diodes are spec'd at different currents:
    1( A BZX79C5V6 is spec'd at 5mA and has an internal resistance of 40 ohms.
    2) A BZX85C5V6 is spec'd at 45mA. At 5mA its voltage is about only 5.3V and its internal resistance at 5mA is 80 ohms, so regulates half as well as the low current zener diode.

    The higher current zener diode regulates very well at very high currents within its power dissipation rating.
     
  4. dave

    Dave New Member

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  5. redart

    redart New Member

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    Thanks for the replies guys, and yes Nigel....I have heard of Google!. I used it to find the datasheets for both series, but they don't exactly read like a walk in the park for the novice, hence the question.
     

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