Tank Circuit

Discussion in 'General Electronics Chat' started by VishnuMS, Sep 21, 2010.

  1. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    I know little about tank but have heard of them producing damped oscillations.... Is there any oscillator that uses this as a signal source rather than a filter
     
  2. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    People Respond Please ................
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
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    It is 2:30 in the morning on the east coast of the USA. It might take a little while to get a response...more than 9 minutes..

    Most are lucky if they get a response in 2 days.

    Here is some info that could help you with tank/resonator circuits:
    http://www.allaboutcircuits.com/vol_2/chpt_6/2.html
     
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  4. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    Okay ... Sorry......... and that link is great.....But i need to know just one thing.....

    "often we use this circuits in feed back loop as filter, even though it has an inherent property of oscillation. I haven't yet seen any oscillator using tank as a signal source. So I want to know if there is one"

    Great thanks for replay anyhow
     
  5. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    Anybody there............................................................
     
  6. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    Is there anyone .........................................................?!/
     
  7. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    Okay what time is it now??????????????
     
  8. beenthere

    Retired Moderator

    Apr 20, 2004
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  9. Nik

    Well-Known Member

    May 20, 2006
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    Google for LC oscillators. There's Hartley & Colpitt, to name but two. Also, you can put an LC on a negative resistance circuit of several topologies...
     
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  10. PRS

    Well-Known Member

    Aug 24, 2008
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    The tank is widely used to create sinewaves. A transistor is used to amplify a signal whose frequency is determined by the tank's resonant frequency. A positive feedback path to the input of the amplifier causes the signal to be amplified and reintroduced to the tank. A perpetual sinewave is therefore set up and remains until either the power is removed or the feedback loop is broken. As several posters pointed out above, there are standard types such as the Hartly and the Colpits. Google these and you'll find thousands of example circuits.
     
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  11. marshallf3

    Well-Known Member

    Jul 26, 2010
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    In ham radio a tank circuit is usually a capacitor and inductor in parallel.

    In many cases the inductor will go to the power supply and the cap to the ground since, at RF, they're exxenstially the same point.
     
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  12. Wendy

    Moderator

    Mar 24, 2008
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    The nearest thing to what the OP wants is a crystal radio. A LC circuit needs an external source (such as radio waves) to be excited. In the case of an oscillator the amplifier provides the excitation for the LC part. To start oscillation most oscillators (not just LC) require random noise that is present in almost all amps to jump start it.
     
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  13. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    Okay I understand ...But Beenthere, if it where a chat room, as the software dudes do, then it could have been more useful,......... and from here on I'll be patient ........Thanks....Your participation is most awaited

    NIK, Thanks for your replay, but all those oscillators use tank as feedback filter. Please read the rest of my replay

    PRS, I really wanted to hear something like this man .Could you just provide a circuit and its AC equivalent along with explanation pls.Great thanks for replay. Please read my replay to Bill_Marsden

    marshallf3, Thanks , I think you are telling about the High Frequency AC Equivalent, right?

    Bill_Marsden, Okay the noise you mention here is the thermal noise in Resistors at input part of AMP, am I right. I have heard such a thing. This noise is quite considerable. And according to this definition the tank has no role as a signal source. And that's what my question is. Look, according to PRS, the signal originate from tank and gets filtered later by the tank itself. But I haven't yet seen such a circuit/Equivalent/Block diagram, pardon my limited knowledge. But I have seen circuits/block/equivalent of what you stated. Also if there is something like, what PRS says, then Oscillators should be like this...



    Tank as
    Signal Source |--->|AMP |---> output
    ^
    |___________________________|


    So....??????????

    AND I AM EAGERLY WAITING
     
    Last edited: Sep 23, 2010
  14. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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  15. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Why don't we just simplify the word "tank" into "frequency selective"
     
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  16. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    nsaspook, that's amazing ..........Thanks


    marshallf3
    , Hi,....Good to see you back...........What you said is what I want to do but ...........What about its unit impulse response?!...........

    Does that response has something to do with the oscillations setup in an oscilator
     
  17. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Don't even know what "unit impulse response" would infer, to me a tank circuit is just a resonant circuit built from electronic components or in the case of high power &/or high frequency RF it can be a cavity.

    It exhibits a primary resonant frequency and a Q.
     
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  18. BillB3857

    Senior Member

    Feb 28, 2009
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    I may be way off but to me a Pulse Input Response would be similar to the old (1950-60 vintage) radar system range mark generators. (Those are the round concentric rings you see whenever a radar scope is shown in the movies) A tank circuit was pulse excited with the synchronized pulse equated to the firing of the magnetron. The resonant frequency of the tank circuit produced a ringing frequency equated to the desired range mark time. Whenever the synchronized transmit pulse occurred again, the ringing was locked down and the release of the pulse allowed the tank circuit to start ringing with the proper phase relationship to keep range marks constant on the scope.

    The "Q" of the tank circuit determined how quickly the AC output decayed. Since we were only interested in less than ten cycles, typically, there wasn't a very noticeable reduction in amplitude. The output was the shaped up and small pulses representing the positive peaks were generated to actually go to the display
     
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  19. Wendy

    Moderator

    Mar 24, 2008
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    The ringing of an LC circuit doesn't actually feed anything, it isn't an oscillator in and of itself. You can also use resistors and capacitors to make a frequency selective network. You can also use a crystal, which electronically is equivalent to a complex LC network.
     
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  20. VishnuMS

    Thread Starter New Member

    Sep 21, 2010
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    marshallf3, WhatI know impulse Response is, What's stated here

    http://books.google.co.in/books?id=pT7ZTE8RlkUC&pg=PA190&lpg=PA190&dq=Unit+Impulse+Response+of+parallel+LC&source=bl&ots=4qNPRU_TPX&sig=bcj64DQtbWnT4aCoF0kA8E7Ezq0&hl=en&ei=3CugTMfYFI7evQPMz5mvDQ&sa=X&oi=book_result&ct=result&resnum=5&ved=0CC0Q6AEwBA#v=onepage&q=Unit%20Impulse%20Response%20of%20parallel%20LC&f=false

    Sorry for the delay...........Please tell me what the above link really infer

    BillB3857, Only Thanks ....Sorry..... because I don't even know tank properly and you are telling about radar man ......... that's too much for me
    ''''''''''Ha Ha Ha''''''''''''''


    Bill_Marsden, Just go through the link .....I think it will make you think again before you say that the next time
     
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