Split rail power

Discussion in 'General Electronics Chat' started by vpoko, Apr 20, 2012.

  1. vpoko

    Thread Starter Active Member

    Jan 5, 2012
    I did just recently post a power supply related question; I thought about adding this to that thread but I figure it's a different enough question to warrant its own thread.

    When using a DC bench power supply with multiple outputs that can be connected in series, I understand it's possible to have a split rail supply. The power supply I'm looking at (Mastech HY3005D-3) allows 0-30V on each output, but the specs don't mention being able to go to negative voltages. Does this mean if I use it as a split rail supply, I will have to choose a positive voltage as my reference ground? For example, if I need -15V, 0V, and 15V I'd have to choose 15V above earth ground as my reference ground? If I'm right, what are the implications for connecting an oscilloscope to such a circuit? Since the scope is connected to earth ground, wouldn't that create 15V of potential across its ground lead? Do I need a supply with a different feature set if I want to be able to get both positive and negative voltages out of it, with the ground being tied to earth ground? Thanks!
  2. t06afre

    AAC Fanatic!

    May 11, 2009
    No it is quite simple. See the picture. Here I am using two 9 volt batteries. But the principal is the same for your two power supplies
    vpoko likes this.
  3. vpoko

    Thread Starter Active Member

    Jan 5, 2012
    Wow, it really is simple when you put it that way, thanks! Talk about a picture being worth a thousand words...
  4. Wendy


    Mar 24, 2008