diode

Discussion in 'General Electronics Chat' started by one 2 3, May 24, 2010.

  1. one 2 3

    Thread Starter New Member

    May 24, 2010
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    search information about diodes
     
    Last edited: Jul 16, 2010
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Are you thinking of the commonly used practice of drawing the equivalent circuit of a transistor as two back-to-back diodes with the base as the common connection point?
     
  3. Bychon

    Member

    Mar 12, 2010
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    Are you referring to the diode often shown in drawings of MOSFT transistors?
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,648
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    Hello,

    The schematic is unreadable.
    Please repost it with a white background.

    Bertus
     
  5. hobbyist

    Distinguished Member

    Aug 10, 2008
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    It looks like the collector of an NPN is conected to a relay coil, so I would think maybe to prevent inductive kick back, from flowing back into the transistor, this diode will bypass the inductive spike around the transistor to ground.

    Usualy a diode is put across the relay coil itself, to prevent this.
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
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    I agree that the negative schematic can barely be seen, even when I make a negative of it. It has lines all over the place.

    The diode across the collector and emitter of the transistor does nothing and can be removed. The diode across the relay coil arrests its high voltage spike.
     
  7. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
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    You can put a zener across the collector and emitter to eat spikes too. Some ECU's do this with their fuel injector drivers.
     
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