tank circuit using radioshack electronic sensorslab 28-278

Discussion in 'The Projects Forum' started by overmyhead, Nov 6, 2009.

  1. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    this is what i have to work with built into the kit is a 8Ω & 1000 Ω transformer 2 LEDs,2 resistors(size ? ) capacitor (size ?) what i need it to do is oscillate with the LEDs showing the curuit flowing between the transformer (inductor) & capacitor
     
  2. mikediv

    New Member

    Nov 4, 2009
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    Hi I am not clear if you want to blink and LED you are going to need some kind of flip flop or something else a cap and resistor will not cut it, do you have any transistors? If I am wrong and you just want to show power from transformer to LED thats easy you can just use one of your transistors in front of the LED and to ground if you have more than one LED they are like Diodes and you could build somehting a little more fancy.. Oh and when you say kit does it have more components? maybe you can list what you have
     
  3. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    I HAVE TO KEEP IT SIMPLE 2 LEDs,2 resistors, cap,ind(transformer1000Ω)cap chargers & discharges 1 LED blinks when inductors magnetic field collapes reverses polarity the other LED blinks the oscillating between the cap & ind blinks the LEDs it has to be balanced to work right
     
  4. CDRIVE

    Senior Member

    Jul 1, 2008
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    An Oscillator requires positive feedback. How are you going to accomplish this without an amplifier?
     
  5. CDRIVE

    Senior Member

    Jul 1, 2008
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    I should have mentioned that, as per your topic title, you do have enough components to build a Tank Circuit though.;)
     
  6. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    iam using a 10v dc power supply to charge the cap when i cut the power the inductor will disapate recharge the cap cap discharges charging the inductor thats the ocillating if you look at the tank circuit on this site just add 2 LEDs & 2 resisters my ? is will the 1000Ω transformer work as the inductor if so what cap will balance the circuit where to put the LEDs & resistors & what polarity the only large cap i have is 470
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    Sorry, but the oscillations in the tank circuit will dissipate very rapidly due to the parasitic resistance in the circuit. If you add LEDs and resistors, the oscillations will dampen out more quickly than you could see them.
     
  8. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    You can make a homemade inductor and build a "joule theif", using a single transistor, one resistor, and the coil.

    If your multimeter has a frequency counter, it will show the frequency (20-50kHz), or better yet, a scope.

    Tank circuits operate at frequencies that high, so it isn't something you can "see" without a scope.
     
  9. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    I dont have a oscope at home its in the lab. Cant get to it till this is done on monday. I think it will charge & discharge in 1/12 th of a sec. I know just using a 1000Ω transformer & 1 LED & 1 resister you can see it blink same with a cap just got to work in parallel. I know it will not be much does anyone know how much resistance the diff color LEDs have. Iam new to this stuff & if I dont get circuit built I will fail the class. Dont I need a resistor for each LED so I dont burn it up? I will need to know total resistance of this circuit too
    NOT REAL SMART ON THIS STUFF HEEEEEEEEEPL
     
  10. CDRIVE

    Senior Member

    Jul 1, 2008
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    What site?
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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  12. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    Last edited: Nov 7, 2009
  13. CDRIVE

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  14. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    still need help I know Iam a little brighter than a burned out LED time is running out and I dont want to fail this class
     
  15. CDRIVE

    Senior Member

    Jul 1, 2008
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    Are you certain that your instructor wants you to build a LC oscillator to light two LEDs and not a RC Flip Flop? Or is it possible that he just wants you to use the 120V Pri/12V Sec Transformer to light the LEDs? I ask because this is a weird assignment with very few components to accomplish the task .
     
  16. SgtWookie

    Expert

    Jul 17, 2007
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    For some reason, the link our OP posted didn't work.

    Here's the page they were referring to: http://www.allaboutcircuits.com/vol_6/chpt_4/15.html
    [eta]
    Oh, I see it now - they added an "a" in "chpt_4" to make it "chapt_4"; no workee.

    Well, down to the wire, and no good news.

    It's really a bit late to try to do something with this.

    Tank circuit oscillations will die out quickly with no excitation to keep them going. Add a load, and they'll come to a screeching halt.

    What voltage are you using to excite the tank? Can you keep the battery connected to a portion of the tank for a ground reference, and things outside the tank?
     
    Last edited: Nov 8, 2009
  17. CDRIVE

    Senior Member

    Jul 1, 2008
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    After looking at that link I would think that the OP would have a better chance of seeing a light flash by using a NE2 and resistor on the 120V side of the xfmr, but I haven't run the numbers.
     
  18. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    no more than 10 v dc does not have to run very long 10- 30 sec just to see the oscillation
     
  19. CDRIVE

    Senior Member

    Jul 1, 2008
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    Are you saying that your instructor has given you this assignment and he expects a simple tank, that's momentarily juiced by a power source, to oscillate for 10 to 30 sec??? If so, you better find another instructor!.... Really!!
     
  20. overmyhead

    Thread Starter New Member

    Nov 6, 2009
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    He gives this circuit to everone to build as a test done it for years it can be built with 4 componets says we can use up to 6.a nonpollarize cap balances a inductor 2 small resistors 2LEDs in a par circuit got to get the LEDs & resistors in the right order & #s to balance it all out
     
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