Amplifier Design

Discussion in 'The Projects Forum' started by lmacb22, May 26, 2012.

  1. lmacb22

    Thread Starter New Member

    May 26, 2012
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    Im trying to come up with a design that would meet the following requirements: Input at 200 Hz @ .2Vpp in series with 4.7k resistor. And the output has to be 1Vpp across a 470 ohm resistor with minimum distortion. I tried using two 2N3904 JFETS and still could not get the output correct.
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,107
    3,038
    An op-amp would make short work of this.
     
  3. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    2N3904's are NPN BJT. They are not JFET's.
     
  4. lmacb22

    Thread Starter New Member

    May 26, 2012
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    how would I use an op amp to make it work?
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,107
    3,038
    Try this.

    You need a gain of 5. About your only concern is the ground. If your signal is only 0.2V above ground, you'll need a dual supply or an op-amp that can sense all the way to the ground rail. Otherwise the few mV or more at the bottom will not be reliably amplified.
     
    lmacb22 likes this.
  6. absf

    Senior Member

    Dec 29, 2010
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    lmacb22 likes this.
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