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Author Topic: Resonance Circuits and Resonance Systems  (Read 69804 times)

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #120 on: September 30, 2017, 10:15:24 PM »
More coil related questions:

I can find out the resonant freq of a primary, by using this method:

http://www.hvtesla.com/img/tesla%20coil%20tuning_prim.jpg

Then I can make the secondary so that it also resonates with that frequency.

Now what if I have a 15kV flyback transformer to drive the primary? How do I measure my primary to resonate to the freq that the flyback produces? Or do I just connect a cap and spark gap to the circuit and change the cap values to find the resonance? What methods can I use to find that resonance, because I can't just connect an oscilloscope to a coil that has 15kV running through it? If I use another coil, maybe just few turns, and hold it near the primary. I can see spikes, but doesn't this just show the resonant freq of the short coil that i'm holding and not the primary's resonance?

Belfior

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Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #122 on: October 30, 2017, 08:34:48 PM »
Trying to make a transistor switch this circuit automatically to get over 100V from a 6.5V DC battery.

https://www.youtube.com/watch?v=EVK84Z8BSnc

Would appreciate if someone could take a poke at this maybe with

https://www.circuitlab.com

and no I would not like to use a voltage doubler, tesla coil, joule thief or any method to raise voltage. Just an automatic switch for this solution on the video.

My current non-working idea is at https://www.circuitlab.com/circuit/szm2y68b4wqt/voltage-pump/

and yes I am not an electrician. My idea was to zap the coil to the battery negative using the transistor's collector and emitter. When they conduct base loses voltage and shuts of collector&emitter. Resulting magnetic field in the coil collapses and the energy has no place to go but the cap

TinselKoala

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Re: Resonance Circuits and Resonance Systems
« Reply #123 on: October 31, 2017, 03:22:33 AM »
You're on the right track, sort of.

Google "disposable camera schematic", and have fun.

But be careful, you can get a powerful shock or even damage your skin.

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #124 on: October 31, 2017, 08:00:47 AM »
You're on the right track, sort of.

Google "disposable camera schematic", and have fun.

But be careful, you can get a powerful shock or even damage your skin.

Whaaat! No way! Maybe small resistor on the collector side also and test this by attaching a gas discharge tube and a lamp over the capacitor. This way the high voltage would ZAP to something. hopefully

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #125 on: October 31, 2017, 09:38:07 AM »
Hmm if you check the circuit here

http://tinyurl.com/yar2enzh


Why doesn't the current going through collector&emitter stop the voltage on the gate? I thought collector&emitter conducting would stop the base from getting the voltage and then shut off?
« Last Edit: October 31, 2017, 09:27:01 PM by Belfior »

TinselKoala

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Re: Resonance Circuits and Resonance Systems
« Reply #126 on: October 31, 2017, 06:04:48 PM »
If you let your sim run for a while you 'll see that there is a small current flowing
from the capacitor, through the base and out the emitter of the transistor. This
is what is keeping the transistor turned on. I think you need a "pulldown"
resistor or other means to allow the base to go Low and turn the transistor off.

I think.



Also the huge long link has screwed up the forum page, so you need to scroll all the way to the
right to see the response buttons.

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #127 on: October 31, 2017, 09:36:38 PM »
If you let your sim run for a while you 'll see that there is a small current flowing
from the capacitor, through the base and out the emitter of the transistor. This
is what is keeping the transistor turned on. I think you need a "pulldown"
resistor or other means to allow the base to go Low and turn the transistor off.

I think.



Also the huge long link has screwed up the forum page, so you need to scroll all the way to the
right to see the response buttons.

Even the mosfet version fails http://tinyurl.com/y9sxb3df

sorry about the link. Using the tinyurl-conversion on the software now

TinselKoala

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Re: Resonance Circuits and Resonance Systems
« Reply #128 on: November 01, 2017, 09:58:05 AM »
Too complicated and doesn't quite capture the concept.

Try this:

http://tinyurl.com/y7jgmrko

By the way... I can charge a cap to 15 times the supply voltage using only a relay and a diode. Figure this out and you'll catch the concept.

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #129 on: November 01, 2017, 10:48:04 AM »
Hmm ok so difference to my mosfet circuit was that you have no resistors. Gotta check this out in the real world. Thx!

I wonder if you can do this with the coils resonant freq and if that gives you a boost?

Magluvin

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Re: Resonance Circuits and Resonance Systems
« Reply #130 on: November 01, 2017, 11:02:51 AM »
Hmm ok so difference to my mosfet circuit was that you have no resistors. Gotta check this out in the real world. Thx!

I wonder if you can do this with the coils resonant freq and if that gives you a boost?

Hey Belfior

Pick up a couple books on switching power suppllies or do some online search for these.  Some books I have taken it all the way to explain about 'staying away' from resonance freq of the transformers or inductors and try to be at least 10 times below the self resonant freq and stay off of harmonics there of also.  Well since your in the resonance topic, lets do just that and break the rules.  ;)

Ill see what I can come up with to try some things.  Typically the self resonant freq of an inductor or power supply transformer is pretty high. So in your design, I would work it out to have some freq around 50khz or so.   If it were a 50khz power supply design then the transformer they would recommend would have a freq around 500khz.  But those supplies dont have hundreds of turns, if you have ever taken a switching supply transformer apart.  So the turns number needs to increase using smaller wire and do some bifilar windings to increase the capacitance, or add a cap to a winding.  Those kinds of things first to get a workable resonant freq going in the coil or transformer. Then work on a driver for it.

Mags

Magluvin

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TinselKoala

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Re: Resonance Circuits and Resonance Systems
« Reply #132 on: November 01, 2017, 11:36:33 AM »
Hmm ok so difference to my mosfet circuit was that you have no resistors. Gotta check this out in the real world. Thx!

I wonder if you can do this with the coils resonant freq and if that gives you a boost?

Also check your PMs. Replace the square wave generator with a 2 terminal type, connect up the second terminal to ground (negative rail) to avoid the floating gate problem and make the mosfet switch properly. Too big an inductor means too slow a spike. Note that the _current_ from the inductor continues to flow _in the same direction_ when the mosfet switches off, and the inductor's _voltage_ as shown on the scope shows the spike as _negative_ because the inductor effectively switches polarity (bottom terminal becomes positive) when mosfet switches off.

http://tinyurl.com/y9hzs47k

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #133 on: November 01, 2017, 06:03:49 PM »
Look for switching or regulated power supply books by Irving Gottlieb

https://search.yahoo.com/search;_ylt=A0LEV1QdnPlZc_4AjotXNyoA;_ylu=X3oDMTEzaWQ3NWZvBGNvbG8DYmYxBHBvcwMxBHZ0aWQDQjQ0ODJfMQRzZWMDcmVs?p=irving+gottlieb&ei=UTF-8&fp=1&fr2=rs-top&fr=yfp-t

Mags

Wanted this from Gottlieb "Practical Oscillator Handbook" but it is 100$! Maybe for xmass then...

now that I got the voltage pump circuit figured out I ill start blasting my 90V GDT to a coil. That means be basically have unlimited free energy available pretty soon!

Need to start buying aluminium hulls for my spaceship now that the power supply is almost finished...

Belfior

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Re: Resonance Circuits and Resonance Systems
« Reply #134 on: November 04, 2017, 07:57:16 PM »
Too complicated and doesn't quite capture the concept.

Try this:

http://tinyurl.com/y7jgmrko

By the way... I can charge a cap to 15 times the supply voltage using only a relay and a diode. Figure this out and you'll catch the concept.

Ok first I thought this is just theory and will not even work. Don't know if my IRFP260Ns are just cheap copies. But the circuit did not work with it. Replaced it with 2N3055 and something started happening. Now I get my WIMA 0,047uF 2000V cap charged to 230V and it fires through a 90V GDT into a coil nicely. Great system and small in size to do all kinds of spark gap testing!