Faulty ground path

Discussion in 'General Electronics Chat' started by Zortz, Sep 6, 2014.

  1. Zortz

    Thread Starter New Member

    May 2, 2014
    16
    0
    Hey!

    I had problems programming my PIC controller and started investigating my circuit, I found this:
    Isolated circuit, power enbled, ground connection disabled. Still working...
    Since in lacks connecton to ground it finds the way into LCD module ground wire, from there through LCD pin wires it moves to my PIC port pins and from PIC it moves to main ground.
    It feels very abnormal.
    I am beginner so i dont know what to think about this..should i start dioding my ground connections?

    Thank you!
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,500
    2,365
    An actual circuit may help in diagnosing the issue?
    Max.
     
  3. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,790
    827
    Max. Ya think?

    Zortz, can you supply some additional information, such as a schematic.

    I've been drinking beer out of my crystal ball today, and it's not working well.
     
  4. tom_s

    Member

    Jun 27, 2014
    285
    333
    too cloudy. use a straw straight from the bottle :)
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,415
    3,354
    CMOS integrated circuits operate on very little current, sometimes as low as 1uA and lower.
    Sometimes a CMOS IC will function even when the Vcc or Vdd (power pin) is not connected.

    How come? Because a signal connected to an input pin can supply enough current via the input protection diodes, sufficient current to activate the device.

    The same thing can happen with GND or Vss pins disconnected.

    The bottom line? Check all your power and ground pins to make sure they are properly connected.
     
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