please help! how does the circuit work

Discussion in 'General Electronics Chat' started by Harshit Agarwal, Jan 26, 2016.

  1. Harshit Agarwal

    Thread Starter New Member

    Jan 26, 2016
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  2. WBahn

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    Mar 31, 2012
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    What's the context of the question? Otherwise, "It works by applying 9 V between the top and bottom nodes," would be a valid response.

    Is this a homework problem?
     
    Harshit Agarwal likes this.
  3. crutschow

    Expert

    Mar 14, 2008
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    It's an astable multivibrator as described here.
     
  4. Harshit Agarwal

    Thread Starter New Member

    Jan 26, 2016
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    not a homework problem ,seen this somewhere and wanted to understand it
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    So I would recommend taking a look at the link that crutschow posted, if you haven't already, and see if that satisfies you. If not, then by all means come back and try to post a question or three that get at what part of the operation is vexing you. That should provide much better targeted help to address your confusion.
     
  6. hp1729

    Well-Known Member

    Nov 23, 2015
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    Assuming Q-left comes on first the collector moves toward +9 , discharging C-left, holding Q-right off. Eventually the capacitor drains and the resistor R-right pulls the base of Q-right to ground, turning it on. This discharges C-right, turning Q-left off. Eventually C-left discharges and resistor R-left turns Q-left back on which turns Q-right off ... all the magic is in the timing of the capacitors and the base resistors.
     
  7. cmartinez

    AAC Fanatic!

    Jan 17, 2007
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    To me, this circuit is a perfect candidate for simulation in LTspice that the OP could use as a playground, so that he could see for himself what would happen if he were to change or tweak the values of the components, and learn something along the process.
     
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  8. hp1729

    Well-Known Member

    Nov 23, 2015
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    Emulate? Only ten parts. Build it.
     
  9. cmartinez

    AAC Fanatic!

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    That too :)
     
  10. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Easy for you to say. You have a scope. :D
     
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