Designing an end user appliance...

Discussion in 'General Electronics Chat' started by ScorpFire, Dec 29, 2009.

  1. ScorpFire

    Thread Starter Member

    Jun 4, 2009
    13
    0
    Hi guys i am designing an appliance and have some problem. My appliance will be plugged into the mains, like this

    [​IMG]

    Now inside this box i have some circuits. Some of my circuits need a ground like this
    [​IMG]
    Where can i connect this to? Can i connect it to the Earth wire on the 3pin plug? The green/yellow wire...

    [​IMG]
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    You should post some diagram of all the circuits, so that we can tell you how it should be connected.

    Are those circuits of your design, or just some factory-made "standard" boards?
     
  3. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    In the United States, the earth ground connection is used only as a safety ground. The green wire should, under normal operation, carry ZERO current. In the event of equipment failure, the green wire will insure that the case of the equipment will not assume a voltage level above ground potential.
     
  4. ScorpFire

    Thread Starter Member

    Jun 4, 2009
    13
    0
    [​IMG][​IMG][​IMG]
    Ok assume i have this circuit.

    [​IMG]


    Im currently at home, i have a breadboard with all the components. I have a +5 voltage power supply, but where can i get a ground?[​IMG]
     
  5. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    the ground should come from the +5 supply...... it should be marked as -
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    If you are grounding the chassis of your appliance then it should be grounded to the earth ground. This is a safety feature.

    If you are just trying to show a common connect point similar to ground (but not ground) I use a triangle that looks similar on my schematics.
     
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