about this low frequency amplifier

Discussion in 'General Electronics Chat' started by wolffzheng, Jan 15, 2010.

  1. wolffzheng

    Thread Starter New Member

    Nov 6, 2009
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    The gate at the bottom of the schematic diagram acts as a linear low frequency amplifier, due to the negative feedback resistor R3. But I think IC1d is only an oscillator, so how IC1d acts as a low frequency amplifier?
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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    It appears that what you have is two oscillators each oscillating at a slightly different frequency. The resulting output is the difference and the sum of the two frequencies. The lower frequency is the one that is dominant.

    hgmjr
     
  3. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    The 1Meg feedback resistor forces the output voltage to equal the input threshold voltage. Since the 4011 has voltage gain, it will act as an amplifier.
     
    Last edited: Jan 15, 2010
  4. Audioguru

    New Member

    Dec 20, 2007
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    IC2a and IC2b is the first slow oscillator that gates the second audio oscillator IC2c and IC2d on and off.
     
  5. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    I should add that Ic1d is not an oscillator. (Unless I use it. Then all amplifiers are oscillators.):rolleyes:
     
  6. hgmjr

    Moderator

    Jan 28, 2005
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    I seems to me that IC1d is furnishing feedback to re-trigger the oscillator in order to control the overall period of the oscillation.

    hgmjr
     
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