power supply ground floating

Discussion in 'General Electronics Chat' started by yardcat, Apr 4, 2009.

  1. yardcat

    Thread Starter New Member

    Nov 27, 2008
    4
    0
    Maybe this is a novice question but I haven't found an answer. I want to put several guitar effects circuits chained together in one enclosure. Some circuits are plain 9 volt and some are dual supply +9 and -9 volts.

    My question is, if I use a line operated dual power supply from a CT transformer will I run into trouble with the ground? It seems to me that I will burn out half of the transformer. It is my understanding that a dual supply has a floating ground and the guitar amp's ground, which is connected by the guitar cable is connected to earth ground. Is my understanding right? what should I do?

    Thanks, from someone with a very little knowledge.
    yardcat
     
  2. leftyretro

    Active Member

    Nov 25, 2008
    394
    2
    As long as your dual supply is using a tranformer with a center tapped secondary winding it's OK to connect the center tap to ground and connect it to any other circuit ground.

    Lefty
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    There is no problem if one side of the transformer is loaded more than the other, as long as the current on the more loaded side isn't exceeded. It is standard practice.
     
  4. yardcat

    Thread Starter New Member

    Nov 27, 2008
    4
    0
    So, I can safely connect the center tapped ground to earth ground? If I turn on the power I read an AC voltage of 19 volts between the CT ground and the earth ground of the wall socket. This confuses me.
    yardcat
     
  5. leftyretro

    Active Member

    Nov 25, 2008
    394
    2
    Yes, you can wire them together if you wish. You don't have to do that and if not your supply would be said to be 'floating' in respect to your home power wiring ground. Circuit common and true ground are two different things, however if wired together your circuit ground then becomes a true ground. It depends on what you are doing and the voltage levels being generated in your power supply, if it's advantageous to wire to AC ground or not.
     
  6. yardcat

    Thread Starter New Member

    Nov 27, 2008
    4
    0
    Thanks, Leftyretro, for your information. It helped solve my problem. I will connect the common ground to earth ground.
    I have another question but I guess I should start a new thread if search doesn't turn up anything.
    yardcat
     
Loading...