Amplifiers circuit help!

Discussion in 'The Projects Forum' started by alitex, Dec 26, 2008.

  1. alitex

    Thread Starter Active Member

    Mar 5, 2007
    122
    0
    hi...
    i have low voltage almost lower than 1V (0.1 step) and i want to amplify this signal between 3 to 5V so what is the best circuit for amplify the voltage due
    thanks alot
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    An op amp circuit configured as non-inverting amplifier. What kind of signal is it? What is its frequency?
     
  3. alitex

    Thread Starter Active Member

    Mar 5, 2007
    122
    0
    the kind of signal is vga output ,the frequency is 28 MHz
     
  4. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    A normal opamp will not manage 28 Mhz.
    Take a look at the Intersil EL8102.

    Greetings,
    Bertus
     
  5. hbkamit

    New Member

    Dec 27, 2008
    4
    0
    Why dont u try common base configuration with a gain of 5 to 7?If u need circuit diagram i can sent u.
     
  6. alitex

    Thread Starter Active Member

    Mar 5, 2007
    122
    0
    i can't take 28MHz frequency of it
     
  7. alitex

    Thread Starter Active Member

    Mar 5, 2007
    122
    0
    thanks alot...i think this is what i want.....
    but i have some problems with connect 741 amplifier...
    i can't take the correct tare of amplify .. i want make G=vo/vi=10 but really i can't take accurate results...
     
  8. bertus

    Administrator

    Apr 5, 2008
    15,646
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    Hello,

    The 741 is very old. It can just manage 1 Mhz at gain 1.
    At gain 10 it will just manage 100 khz, this ia much to low for your application.

    Greetings,
    Bertus
     
  9. alitex

    Thread Starter Active Member

    Mar 5, 2007
    122
    0
    what u suggest to me?
     
  10. bertus

    Administrator

    Apr 5, 2008
    15,646
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    Hello,

    In an earlier reply I already adviced the EL8102.
    The complete datasheet is with the earlier reply.
    This is an opamp with a bandwith of 500 Mhz at gain 1.

    Take a look at the gaincurves.

    [​IMG]

    Greetings,
    Bertus
     
  11. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The output of a lousy old 741 opamp has trouble with frequencies higher than only 9kHz when the output swing is high. More modern ordinary opamps have a wide output swing up to 100kHz.
     
  12. italo

    New Member

    Nov 20, 2005
    205
    1
    I am looking at them where is the A -Db
     
  13. bertus

    Administrator

    Apr 5, 2008
    15,646
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    Hello,

    What do you mean with "A -Db" ?
    Did you have a look at the complete datasheet?

    Greetings,
    Bertus
     
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