single supply opamp

Discussion in 'General Electronics Chat' started by asimraufawan, Jul 10, 2009.

  1. asimraufawan

    Thread Starter Member

    Jul 4, 2008
    29
    0
    Hi ,

    i want to use LM741 opamp , do i need a dual supply or it will operate at
    single supply (5v).

    I want to use both inverting & noninverting input as an input & the the output will than be the analog input of PIC microcontroller.

    thanks.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    The LM741 needs ± 5 Volts to work.
    Or 10 Volts single supply.
    The LM324 works from 3 to 32 Volts single supply and contains 4 opamps.
    Just take a look at the datasheet.

    Greetings,
    Bertus
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    A better op amp for low power is the LM324 quad. It is very similar to a 741. Both aren't the best part for audio, but they do work. The LM324 is cheap, goes down to 2V power supply, and is easy to get.

    Op amps as a class don't work well for digital. You need comparitors for that (LM339).
     
  4. millwood

    Guest

    any opamp can work in either single rail or dual rail configurations. all you need to do is to adjust the bias on the input pins.
     
  5. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    An LM358 has two of the four opamps in an LM324.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    An LM741 can't get within 2v of the rails.
    If you use a single 5v supply, you will have an input and output range of from 2v to 3v.

    With an LM358 or LM324, maximum output will be about 3.5v with a 2k load when Vcc=5v.
     
  7. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    Here is a collection of single supply opamp circuits from TI.

    Greetings,
    Bertus
     
  8. russ_hensel

    Well-Known Member

    Jan 11, 2009
    818
    47
    YOu have to be careful not to drive the analog input below 0 ( or so ) and the PIC positive rail. One way to do this is to use a single supply rail to rail op amp with the same supply voltgage as the PIC. Op amp may not perform too well near the rails.
     
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