I cannot understand how this circuit works

Discussion in 'Homework Help' started by 53.411/-2.978, Jul 21, 2018.

  1. 53.411/-2.978

    Thread Starter New Member

    Jul 21, 2018
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    I cannot understand how this circuit works

    What is inductor's duty

    I am not sure about dual zener mabe it can be a transistor

    MOD: Lightened up your image.
    20180704_135707.jpg
     
    Last edited by a moderator: Jul 21, 2018
  2. Dodgydave

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    Jun 22, 2012
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    Me neither, can we have the full picture?
     
    Last edited: Jul 21, 2018
  3. ian field

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    Oct 27, 2012
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    Looks like old American schematic with all the rails at the top - PITA!
     
  4. 53.411/-2.978

    Thread Starter New Member

    Jul 21, 2018
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    I am not sure about the transistor and its pins. It also can be a mosfet or dual zenner. But i am sure about the circuit. Can be a protection circuit to switch on and off the supply?
     
  5. Ylli

    Active Member

    Nov 13, 2015
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    Looks to me like some kind of sweep circuit. C27 is charged through a constant current source consisting of the transistor with 3.3 volts on the base. U33 discharges C27. The op-amp, along with the FET takes the triangular input voltage and converts it to a triangular current flow through the inductors. Perhaps an analog TV vertical deflection circuit?
     
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  6. Dodgydave

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    Well the fet is drawn to the wrong supply, it should have it's Drain to +24V,
     
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  7. 53.411/-2.978

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    Jul 21, 2018
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    You are right. In your mind what is this circuit?
     
  8. Dodgydave

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    I think you've traced it out from a pcb, and it could be a Vertical Timebase module for an Oscilloscope , or Sawtooth generator, you might have drawn it wrong.
     
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  9. 53.411/-2.978

    Thread Starter New Member

    Jul 21, 2018
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    Your right. Its a exam. I am sure that i draw it right. Just I am not sure about the ttansistor
     
  10. Aleph(0)

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    Mar 14, 2015
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    @53.411/-2.978 FWIW I agree with other posters saying it's some sort of multivibrator but I totally have to admit that schematic is tying my brain in knotso_O!
     
  11. 53.411/-2.978

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    Jul 21, 2018
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    yes. It seems too strange;)
     
  12. 53.411/-2.978

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    Jul 21, 2018
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    But I think its seems a circuit that switch on and off a voltage that is generated like a protection circuit by by command of FPGA by sensing for example voltage or current.
     
  13. MrAl

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    Jun 17, 2014
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    Hello,

    Here is a slightly more readable drawing.
     
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  14. 53.411/-2.978

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    Jul 21, 2018
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    So whats your idea?? (Nc means that it has no connected and placed on Pcb boad)
     
  15. MrAl

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    Jun 17, 2014
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    Hi,

    I did not study the circuit yet just took a quick look and my idea is that you should get a better camera :)

    Ok all i see so far is that they may have wanted to save money on the inductor so they used two smaller ones in series.
    It could be a power supply although i did not look up any part numbers yet.
     
  16. MrChips

    Moderator

    Oct 2, 2009
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    TS needs to confirm the source of the drawing. Was the drawing created by the TS by reverse engineering a PCB or was the drawing from another source?
     
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  17. Ylli

    Active Member

    Nov 13, 2015
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    No, these are deflection coils, one top, one bottom (or one left, the other right). I reiterate my post #5.
     
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  18. 53.411/-2.978

    Thread Starter New Member

    Jul 21, 2018
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    Hi. No it is drawn by reverse engineering a PCB.
     
  19. 53.411/-2.978

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    Jul 21, 2018
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    Could be a power supply?? Voltage refrence 1.2 v create a -15 volt at positive pin of op amp and it is campared to the source voltage of mosfet then the mosfet is turned on.
     
  20. 53.411/-2.978

    Thread Starter New Member

    Jul 21, 2018
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    what is a deflection coil??
     
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