Tl072 inverting amplifier unsymmetric output...

Discussion in 'General Electronics Chat' started by AJIN NADH, Dec 18, 2014.

  1. AJIN NADH

    Thread Starter Member

    Dec 18, 2014
    79
    4
    Hi,
    Am facing a problem that my inverting amplifier(tl072 ) is not working properly beyond +3.5v , -4.0v.
    Giving a supply vltage of +5v at pin 8, -5v at pin 4.what will be the uissue...?
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    3,957
    1,097
    Every think is fine with your op amp. You simply never heard about maximum output voltage swing.
    The maximum output voltage swing is the range of voltage that an op amp physically provide at its output.
    With a power supply of +5V/-5V, and an ideal amplifier that can swing its output voltage just as far as power supply rail voltages (+5V/-5V).
    But most real world op-amps cannot swing their output voltages exactly to +V/-V power supply rail voltages.
    And this is why you have +3.5V and -4V max at the output. If you want to get closer to supply rails you need to use “rail-to-rail” op amp.
    http://e2e.ti.com/blogs_/archives/b...nges-input-and-output-clearing-some-confusion
     
  3. AJIN NADH

    Thread Starter Member

    Dec 18, 2014
    79
    4
    thanks for the response..
    is it possible to use TL072 as a single supply (ie.pin 4 to ground) , what will happen if it connect....
     
  4. Jony130

    AAC Fanatic!

    Feb 17, 2009
    3,957
    1,097
    For sure you can use a single supply to power TL072 but remember that supply voltage must be larger than 7V. Also don't forget about input voltage range (input common-mode voltage range).
    And the most important part is that if you want to use a op amp as a amplifier you have to bias the op amp somewhere in the middle of his "linear region" with a resistive divider at the positive input terminal.
    See the example circuit

    96_1320874827.png
    Voltage divider (R1 and R2) provide bias voltage.
    Rf and R3 set the AC voltage gain.
    Cin and Cout - coupling capacitors
    C1 - bypass capacitor
    R4 - pull-down resistor
     
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