virtual ground

Discussion in 'General Electronics Chat' started by cryosar, Dec 13, 2009.

  1. cryosar

    Thread Starter Active Member

    Apr 2, 2009
    What is virtual ground in power supply? Can anybody explain me about using virtual ground in delta connection?
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    I'm guessing you are referring to the neutral point in a 3-phase delta connection [such as in a 3-phase transformer delta connected winding] in a power supply/distribution system.

    Is that what your question relates to?
  3. SgtWookie


    Jul 17, 2007
    If you are talking about DC power supplies, you can use a power opamp to "split" a single DC output into two supplies. The output of the opamp maintains a "virtual ground". The supply return/ground becomes the negative voltage.

    From National Semiconductors LM675 datasheet:


    If desired, you could replace the two 22k resistors with a 50k pot; then you could vary the ratio between the upper and lower voltages. I'd put a small cap from the pot's wiper to ground as well; less noise on the reference voltage for the ground.
  4. cryosar

    Thread Starter Active Member

    Apr 2, 2009
    My input is AC only. am asking what tnk has told
  5. GetDeviceInfo

    AAC Fanatic!

    Jun 7, 2009
    3 phase delta is typically an 'ungrounded', or floating supply. If you choose, you could reference any one lead to ground. Care should be taken however, in that a contrary reference hasn't been made elsewhere, or if your using a split/high line arrangement.
  6. Nanophotonics

    Active Member

    Apr 2, 2009
    I understand that the virtual ground is an "ungrounded" node in a circuit that is at 0 V potential. It is more widely used in op-amp circuit analysis.