does this diagram look right?

Discussion in 'General Electronics Chat' started by rfhelp, Apr 5, 2009.

  1. rfhelp

    Thread Starter Active Member

    Mar 23, 2009
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    Is this 1n914 oriented the right way, or is it reversed?


    [​IMG]
    [​IMG]
     
    Last edited: Apr 5, 2009
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Information is limited but looks OK.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    Usually diodes are inserted that way to absorb inductive kickbacks, which can damage drive circuits such as transistors. When a coil goes from full current to none, it generates a reverse voltage and current, sometimes pretty substantal. Just as a capacitor can generate a high current trying to maintain a voltage through a short, a coil can generate high voltage trying to maintain current through an open.

    Only thing that is off is generally a power diode is used, instead of a small signal diode.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    A 1N914 can safely handle 200mA continuous. Most 12V relay coils draw much less than 200mA. Surge current ratings are much higher, but without knowing the relay switching frequency, I would use 200mA as a maximum.
     
  5. rfhelp

    Thread Starter Active Member

    Mar 23, 2009
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    I am using it as protection for spike,

    the relay is this: 12v 5a.

    [​IMG]
     
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Coil current is only 60mA. The 1N914 will work for you.
     
  7. rfhelp

    Thread Starter Active Member

    Mar 23, 2009
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    so the diode is positioned properly in the diagram?
     
  8. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Yes.

    qwertyuiop
     
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