OP-AMP as Voltage Follower

Discussion in 'General Electronics Chat' started by thangadurai, Sep 2, 2009.

  1. thangadurai

    Thread Starter New Member

    Sep 2, 2009
    1
    0
    Hai,
    I am using OP_AMP as voltage follower for buffering the output voltage of the sensor,it gives the output voltage of .5mv to +5v. Is OP-AMP will operate as a voltage follower in this voltage range?.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    It depends on the type of opamp you use.
    At wich voltage are your circuits working?
    There are opamps with "rail to rail" in and outputs.

    Greetings,
    Bertus
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Almost any op amp can operate in that range as a simple follower. A definite answer is hard without knowing details about the circuit, the op amp, and available supply voltages.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    If you use an op amp which is designed to work with single supply it will be able to pull its output down to 0V. To reach 5V you will need to have a positive voltage of greater than 6.5V (depending on the op amp).
     
  5. kkazem

    Active Member

    Jul 23, 2009
    160
    26
    Use a single-supply, rail-to-rail op-amp if your supply voltage is 5V. If it's greater than 6.5VDC, then you still need a single-supply type since your common-mode input voltage range nearly includes ground, but the high-side at 5V depends entirely on your supply voltage. Look at the TI website (www.ti.com) and then op-amp selector guide and there are plenty of single-supply rail-to-rail op-amps and they don't cost that much-perhaps a buck or less on single quantity. You may even be able to get up to 5 of them as free samples (see the TI website).

    Regards,
    Kamran Kazem
    kkazem
     
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