Circuit from behind the spider webs...

Discussion in 'General Electronics Chat' started by Externet, Aug 27, 2016.

  1. Externet

    Thread Starter AAC Fanatic!

    Nov 29, 2005
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    57
    Built this I cannot remember when, for I cannot remember why, and does I cannot remember what.
    Found it with its schematic attached, and of course, untitled...:oops:

    Can you help with what it does ? In my last brain transplant got a refurbished one, not recommended to any.
    P1010633.JPG
     
  2. RichardO

    Well-Known Member

    May 4, 2013
    1,235
    384
    Square wave oscillator with both duty cycle and frequency adjsutments. Note that the adjustments probably interact with each other.
     
    #12 likes this.
  3. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    I think its possible to pad the duty cycle pot so it doesn't.
     
  4. DickCappels

    Moderator

    Aug 21, 2008
    2,658
    632
    You can certainly minimize the duty cycle pot affecting the frequency by making the duty cycle pot much smaller than the frequency pot. For example the duty cycle pot could be 10l while leaving the frequency pot 500K. The maximum frequency shift resulting from changing the duty cycle would be (off the top ofmy head) about 1% (or
     
  5. Externet

    Thread Starter AAC Fanatic!

    Nov 29, 2005
    761
    57
    Hooked to power, produces alternate pulses with slower decay.
    -------|\---------|/---------|\--------|/--------|\--------
    Period adjustable from 4 to 10 seconds.

    Disconnecting the 10uF capacitor, produces a seemingly pure sinewave. One potentiometer controls symmetry and the other, amplitude. Frequency at 50KHz.

    Still cannot tell what I did this for. Any NEW brain available for transplant ? Will pay well.:rolleyes:
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    In the current configuration, the duty cycle will vary from 0-100 % when the frequency pot is at 0K and from 33-67 % when the frequency pot is on 500K.

    Bertus
     
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