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Plasma Speaker, Halloween Project

Discussion in 'High Voltage' started by killivolt, Sep 2, 2013.

  1. killivolt

    killivolt Well-Known Member

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    Here is the first Oscope of the GDT. I have a huge spike before the pulse and then it goes down? Not sure what thats all about, it looks exactly the same as before.

    This is what it's supposed to look like.

    oscope.jpg

    This is my Scope image today. It has a huge spike

    ScopeCapture_zpsc9f9f246.jpg
     
    Last edited: Feb 2, 2014
  2. killivolt

    killivolt Well-Known Member

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    Even though I have a dirty signal, I guess this will be the Test. The Mosfets are loaded and now I just need to connect the Flyback. Since I don't want to smoke anything in my Kitchen. Maybe this afternoon outside.

    1ecbb2ef-ae1c-4bef-ae8d-a15a1d677b20_zpsd38233e0.jpg
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I think the poor contacts and high capacitance between rows of contacts on the breadboard is causing your filthy, dirty signal.
    I made all my prototypes using Veroboard stripboard where every connection was soldered and there were no wires all over the place. My layouts were neat, compact and tidy.
    Even high frequency and high power circuits worked perfectly. The stripboard layouts looks good enough to be sold as the final product for many projects where only one custom circuit was purchased.
     
  4. dave

    Dave New Member

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  5. killivolt

    killivolt Well-Known Member

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    I went through a struggle to get at least one spark the first time round. I started with a stripboard; this thing didn't even whimper, it was dead.

    The Author of this circuit, say's the proper phasing needs to be assured. As you can see it's dirty. But, correctly phased. He also say's it's a good idea to build on a breadboard first. To be fair, I didn't do that the first time round.



    You confirmed my suspicions about the breadboard, capacitance.


    Thanks, Guru.

    kv

    Edit: Feb, 3 2014

    I have been able to finally get some High Voltage on the Flyback. So, now I will Sripboard everything. However, I've been thinking it would be nice to go old school and make this with a "Manhattan" board? Not sure if it will benefit me. LOL

    http://www.qrpme.com/docs/K7QO Manhattan.pdf

    Edit: Edit: I have done some work here on the Gate Drive Transformer ... http://www.electro-tech-online.com/...-center-tap-push-pull-gdt-works.138602/page-3

    I also received help here too! http://www.electro-tech-online.com/threads/building-lt-spice-transformer-help.138524/


    And here...........http://www.electro-tech-online.com/threads/advantages-of-manhattan-style-circuit-boards.139924/
     
    Last edited: Feb 8, 2014
  6. killivolt

    killivolt Well-Known Member

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    So, I stripboarded it and now it's running on 36v with a separate power supply for the Chip. I have lowered the resistance on the 2.2k before the 10k pot. It's now 1.5k.

    My Ammeter on the 36vdc is not calibrated. But, from where it's setting in the off position; I'm probably around 2.5amps above that; I'll have to set the DMM up and see for sure.




    Here's a Scope Image of the (Mosfet Gates)

    FinalSignal_zps7a0c63a0.jpg
     
    Last edited: Feb 9, 2014
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  7. killivolt

    killivolt Well-Known Member

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    I did a second test and it ran for 6 hrs without troubles.

     
  8. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    Getting there!
     
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  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It looks like you have a pretty long arc there. Was it or YouTube clipping the sounds?
     
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  10. killivolt

    killivolt Well-Known Member

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    (Before I put the Diodes 1n4007's and the MKP 1 uF cap in on the Driver circuit) which was intended by the Author; I was able to draw about 3/4" but after placing them back in the circuit it diminished.

    After it was only around 3/8" the clicking was me; I was clicking the Power off and on using a Power Switch from an old Computer Power Supply. It's because one of my Psychology Professors couldn't get his mind around it when I was showing him the original video. He kept saying this is from the arc; an arc? So, I provided an example which could show it was from an arc.

    I'm still waiting for my Inductance Meter; after that I will do some more experimenting to see if I can get a better run out of it.

    I noticed after 6 hrs of run time and my Turning it off and back on to prepare for the Video it was off about 10 minutes or so and had time to cool down; afterward the Mosfets and Flyback had troubles. Probably not a good idea to run it so long. I'm still not sure what happened.

    It was running 24vdc on the Mosfets and had the same arc for the 6hrs. Once I turned it off I had to increase the Voltage to 36vdc to get the same arc; that's when I discovered the problems with the flyback arcing internally and producing an arcing in one of the Mosfets. I was able to tune it with the 10k pot and to start it back up for the final video. I only stopped it to write in my Journal; then I turned it back on for the video.

    I'll rebuild it on a different board and try again with all new parts. I'll keep you posted on the results; I'm also about to received the Copper Clad Boards I ordered they should be in on the 14th around the same time as my inductance meter.

    I just turned it back on and it's still running; after a long day. I didn't expect it too! lol

    Thanks, Guru.
    kv
     
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