Circuit Astable

Discussion in 'General Electronics Chat' started by cheshmayebaruni, Dec 28, 2012.

  1. cheshmayebaruni

    Thread Starter New Member

    Dec 28, 2012
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    Hi I Astabl Op Amp circuit (without chip 555) with a 50% duty variable frequency between 1K to 10k want - Dvstal please help me
     
  2. ScottWang

    Moderator

    Aug 23, 2012
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    You may use google to search - op amp astable multivibrator.
     
  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    In English please.
     
  4. WBahn

    Moderator

    Mar 31, 2012
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    I can't make heads or tails of what it is you have versus what it is you want. I'm pretty sure there are some English-as-non-native-language issues here, but we can work through those. So please reask your question, being a lot more specific as to what you are trying to find out. Keep in mind that we are probably going to struggle with your English and if we can piece together information from different parts of your post it will make that a lot more doable; it is basically an error correcting code -- we need quite a bit of redundancy to work around the language obstacles.
     
  5. cheshmayebaruni

    Thread Starter New Member

    Dec 28, 2012
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    am sorry...

    Circuit Astabl Design with :

    Output frequency Between 1 Khz > F > 10 Khz

    Duty Cycle : 50%

    Opamp Supply : +15 & -15

    Output Voltage wave Pulse : between : 5v > V out > 10v

    Please Help me ......
     
  6. WBahn

    Moderator

    Mar 31, 2012
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    What have you tried so far?

    Is this a school assignment of some kind?
     
  7. Brownout

    Well-Known Member

    Jan 10, 2012
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    The simplest circuit uses a resistor connect from the output to the "-" input, and a capacitor from the "-" input to ground. The capacitor charges/discharges from the opamp's output, and causes the state to switch. In this scheme, you need a resistive network from the output to the "+" input for hysterisis. That provides a deterministice "switch point" for the amplifier. Please consult the internet for circuit details. There is too much information available for this circuit for me to try to produce it here.
     
  8. Wendy

    Moderator

    Mar 24, 2008
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  9. absf

    Senior Member

    Dec 29, 2010
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    You're not allowed to use 555... Is that correct? Only op-amps are allowed?:D

    Allen
     
  10. WBahn

    Moderator

    Mar 31, 2012
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    If you look at the internal block diagram for a 555 timer IC and then figure out what parts you can remove and/or simplify under the condition that you want a free-running ASM, I think you can reduce it to pretty simple op-amp circuit (but I'm just going off the cuff, so I might be wrong and you need something else, but I think that would be a good place to start.

    On a more general note, when told to do something without using X, one of the first things to consider is why is X being excluded? What is it about X that would make the task easier and can you get that same behavior another way.
     
  11. cheshmayebaruni

    Thread Starter New Member

    Dec 28, 2012
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    I have not to use 555.

    only Opamp

    i have Circuit Original form
     
  12. WBahn

    Moderator

    Mar 31, 2012
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    I'm not saying to use a 555. I'm saying to look at the internal block diagram for guidance on how you can implement that part of the 555's functionality that is applicable to your project.
     
    cheshmayebaruni likes this.
  13. cheshmayebaruni

    Thread Starter New Member

    Dec 28, 2012
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    I've answered circuit
    !!!
    I've answered circuit
    [​IMG]
     
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