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I am unsure of what these two symbols are.

  1. Jun 27, 2015 #1
    These two symbols lose me. I am making something for a project and cannot figure the two circled in red out. This circuit is for a disposable camera. flash_unmodified11.jpg
     
  2. jcsd
  3. Jun 27, 2015 #2

    davenn

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    hi

    1)FL1 is the flash lamp

    and

    2) GL1 is a Neon globe or gaseous spark gap ( either will serve the same purpose)
     
  4. Jun 27, 2015 #3
    Oh thanks! :D So Because I do not need those, I can tie L1 into the circuit as opposed to FL1?
     
  5. Jun 27, 2015 #4
    I doubt the circuit will work without them.

    I may be misunderstanding the circuit, but GL1 seems to be part of an oscillator running the autotransformer L1 to charge the flashlamp. You might be able to replace those with different parts. Yet what good is a lamp charging circuit without the lamp?

    I'm sure you'll have fun though. Good luck.
     
  6. Jun 27, 2015 #5

    jim hardy

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    Dave's right.

    GL1 is the "Ready" light that tells you the flash is ready to take a picture, it has charged C1.

    Those things will hold charge for days if GL1 is neon
    always discharge C1 before touching it. 90 volts or so didn't injure me but it did 'come as a shock' .....:oldruck:

    L1 is the trigger coil that makes a several kv pulse to strike the xenon flash tube .
     
  7. Jun 27, 2015 #6
    Here is the thought for a project. I guess if I NEED GL1 I will implement it. But I am not 100% sure I have built the capacitor bank correctly. I need the capacitors to be charged and discharge very quickly. Thus the usage of flash capacitors. I also know the wire from R1 to the relay looks odd. Its just connected to the relay. project.png
     
  8. Jun 28, 2015 #7

    rbelli1

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    In the original schematic everything to the right of C1 is the trigger for the flash bulb and a charge indicator. If you have no flash bulb or charge indicator then you don't need any of it. I would also suggest that you put balancing/bleed resistors on the capacitor bank.

    If you are planning on drawing currents that are large compared with the balancing current then you will need a schottky diode across (anode to -, cathode to +) each capacitor as well. It is probably good to put them there anyway. You might find that the leakage current of the diodes is enough to balance the capacitors.

    BoB
     
  9. Jun 28, 2015 #8

    jim hardy

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    ??? what is it supposed to do ?
    Make a transient magnetic field around what looks like l1 , over there on the right ?

    What limits current through discharge switch ? What is that switch's current rating?
    You can make quite an arc with a flash capacitor.

    Do you understand charge rate is determined by current available through Q1 T1, which isn't a lot ?


    I cant read the print. If you used nine of those 120uf 300volt caps, you now have 80 uf at 900 volts.
    I doubt Q1 T1 will make over 300 volts, but cant say for certain.

    You are building a potentially dangerous contraption here

    What is it you are trying to accomplish?
     
  10. Jun 28, 2015 #9
    I was following a tutorial, http://www.instructables.com/id/The-0-Coil-Gun/ and decided that I wanted to try to make it move faster. The author says that it takes approx. 10 mins or so to charge. So I assumed you either need more amps or more capacitors. However I am still learning. Thus, before I decided to start putting things together and trying, I thought it best to take it somewhere to share my ideas.
     
  11. Jun 28, 2015 #10

    rbelli1

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    With the circuit as is you will not get more voltage or any advantage from using series strings of capacitors. The voltage limit is based on the transformer design. Higher voltage is also more dangerous.

    The easiest way to make it more powerful is to parallel the capacitors. Then you don't need balancing resistors or diodes. You should however us a bleeder resistor across the capacitors so that when you power down they will over time discharge.

    BoB
     
  12. Jun 28, 2015 #11
    What would be the best, and safest, way to implement these things? I guess the barrier comes at my fault of learning. I am literally googling what a bleeder resistor is.
     
  13. Jun 28, 2015 #12

    jim hardy

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    Thanks for telling us what it is you're making. Looks like fun.

    You'll learn a lot - have fun !

    I take it the rightmost coil in your diagram is the big diameter hand wound one in that project link.

    Old CRT type TV or monitor picture tube yokes are a source for secondhand magnet wire..

    We worry here that somebody will make something and hurt themself . That's why i asked.

    PF'ers are a friendly lot. Post your progress?

    Only danger i see in your project is those capacitors can give a nasty shock. Pay special attention to wiring, anything connected to +side of the capacitor needs to be well insulated and / or covered.
    Tiny fingers are curious - if there are small children in your household be doubly careful.

    old jim
     
  14. Jun 28, 2015 #13

    rbelli1

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    You can make a similar device at safe voltage levels. Get a 24VDC power supply and some 50VDC capacitors. This voltage is safe to touch with dry hands. The danger you will have is that a discharge though a low resistance can still burn. Making a coil gun out of this will require a significantly longer wire to wind the main coil and much thicker wires to the capacitor bank.

    Making one at a lower voltage will be a bit harder but there is basically zero chance that is can stop your heart.

    BoB
     
  15. Jun 28, 2015 #14

    berkeman

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    Thread closed temporarily for Moderation...
     
  16. Jun 29, 2015 #15

    berkeman

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    We don't discuss dangerous projects here on the PF. Thread will remain closed.
     
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