Negative Voltage Follower

Discussion in 'General Electronics Chat' started by baseball07, Nov 13, 2009.

  1. baseball07

    Thread Starter Active Member

    Apr 24, 2007
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    0
    Hi everyone. Can a voltage follower be configured for negative voltages rather than positive ones? Say, instead of Vin=Vout=2V, have vin=vout=-2V. Thank you.
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Yes, if you have the required power supplies for the circuit, either dual polarity or "positive ground".
     
  3. russ_hensel

    Well-Known Member

    Jan 11, 2009
    818
    47
    It is not a follower it is a unity gain inverter. Easy if using op amps.
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    What makes you think a follower won't follow negative voltages?
     
  5. alphacat

    Active Member

    Jun 6, 2009
    186
    0
    To the OP
    You just need to worry about the bias point of the transistor.
    If you insert a negative input DC voltage, then you need to make sure that the VEE (or VSS) of the circuit is negative enough in order to have VBE =~ +0.7V (or to have VGS > VTn).
     
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    Did you misread the OP's statement?
     
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