Simple PSU question

Discussion in 'General Electronics Chat' started by erich_7719, Jun 13, 2010.

  1. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    OK, I know how to make a rail to rail PSU Like below, and use the +/-6V rails to get a 12V source; like wise use only the GRD and -6 to get a 6V source (using GRD as a virtual +6 and -6 as virtual GRD).
    [​IMG]
    My question is... Is it advisable to set up the power supply up as shown below for a +12V and +5V if there is now substantial reason for a negative voltage?
    [​IMG]
    Thanks in advance for any opinions and/or suggestions.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I don't know where you found those schematics, but they are not correct.

    The negative output of U1 - DB104 (diode bridge) needs to be connected to the lower side of C4 instead of ground, and T1's center tap needs to be connected to ground instead of the lower side of C4.

    I'm afraid that your idea with the 5v/12v won't work very well, as the 12v regulator will merely output lots of ripple.
     
  3. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    Thank you SgtWookie for your timly responce.
    That was my bad, I just whipped it together real quick and didn't double check polarities before posting.

    The 5v/12v was just an idea that I was curious about, but didn't want to build till I had other opinions on it.
     
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