h-bridge switching ciruitry

Discussion in 'The Projects Forum' started by lihle, Oct 25, 2010.

  1. lihle

    Thread Starter Active Member

    Apr 12, 2009
    83
    3
    guys i need your help here . please try to check where there problem might be. i i have developed an h-bridge using Darlington pair transistor (TP110) and i have try to turn on each transistor using a BJT that switches a 12V to each TP110.but my problem is that it just switches on itself with the bias of the transistor.

    i have attached the design.

    lihle
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Well each darlington has 12V connected via a 1kΩ resistor to its base. It's not surprising they are on.

    Also the drive BC107's will all hard short the 12V supply(s) at their collectors once they are switched on. Bye-bye BC107...???

    Probably time to revisit the design. Where did you get this one?

    Have a look here for instance ....http://www.solarbotics.net/library/circuits/driver_buf_h.html
     
    Last edited: Oct 25, 2010
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Your design has multiple problems.

    Try it like the attached instead.
     
  4. lihle

    Thread Starter Active Member

    Apr 12, 2009
    83
    3
    i did not get it from somewhere but i tried it on my own.

    lihle
     
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