Open Source Project for Tesla/Jackson Wireless Transmission

[cody]

There are many threads about self oscillating circuits on the forum. The joule thief or ss bedini or any variant of exciter should work if designed properly. That would be a simple way to get startedIf my memory is correct i believe slayer posted a simple oscillator circuit on a wireless setup if you do some searching on the forum. A cheapo chinese function generator that would work fine would cost around $100 or so but would not put out 10 or 20 watts directly but could be used to drive higher wattage circuits. You dont need much power to see results though. You can get by without an o-scope by suspending an AV plug near the coil and using a multimeter to look for the peak voltage across the LED as you tune.

I would suggest not starting off with a target in the MHz though. Tesla's system ran around 20KHz and there is good reason to keep your target resonant frequency low.

[Farmhand]

I wouldnt say that. The high frequency alternators used by Marconi were actually tesla's invention. They later became known as alexanderson alternators. Either way they were teslas design and he used them a lot for his wireless system. But yes, for his final design he did say he preferred using DC, but either will work. My main reason for suggesting it is because i think its the easiest way to really comprehend how to tune the system and how different things you do effect the tuning. Personally i have found a function generator with a built in frequency counter to be the best learning tool for understanding tuning of the system. I had built oscillator circuits and ran many tests like you are doing and thought i understood the tuning, but it wasnt until i got a decent function generator that i really got a grasp on it. But thats just me.

I looked at your circuit again and it looks to me like a DC resonant charging circuit except you are using a transistor instead of a spark gap. Thats an interesting idea, i like it. I wonder if it would work better if you put in a de q-ing diode between the battery and the inductors. Here is a typical DC resonant charging circuit. See the first capacitor after the bridge rectifier, that is basically your battery. If you add the diode it shoud ensure that no current flows back into the battery before the transistor fires.



So it would look like this:



If you want to read some of the theory of the circuit and why im suggesting to try a diode you can read here:
DC Tesla Coil design

Yes i see, I would like to try as many things as I can, one of them being an AC square wave. It doesn't make sense to "not' give it a go. If a function generator is not too expensive I will see if i can get one, I should have one anyway by the sound of it.

I actually already have the de-Q-ing diode, it is the IN5408 diode on the top input rail, although I only just realised that is what it is now..
http://public.bay.livefilestore.com/...001.JPG?psid=1

I do these things from intuition but I don't really know why. However for the desulfator it was a bad idea because the return from the charge battery can't get back to the source battery, that is why my 470 uf cap across the rails blew up like a balloon.

I decided to try this method to get some good effect without a spark gap. I imagine that if I use a higher frequency then i will need to use a smaller inductor and cap and vice-versa.

I have a small 6800 pf cap in parallel with the variable cap. which is 40pf to 1300pf, and this seems to work very well as an adjustment window for a 320uH inductor at 50 Khz. But that will all go out the window when i get more frequency.

I wrapped the remaining cylinder above the resonator coil with aluminum to increase the capacitance of the top load and it seems to be better but the foil has edges and there is radiative losses on the foil now as well as the coil.

None of which is really important, until i get resonance I will not know what radiate's what. I think the best option would be an aluminium tube flared at the end and slotted which can be slid over the PVC pipe above the resonator coil, this is where the resonator coil should be attached the top of metal tube then supports the top load. The more the EM wave radiation that is suppressed the better.

The rain is easing so after I mop up some water I'll try to make some neat bases.

Cheers

[Farmhand]

Hi Guys! I'm interested in replicating the wireless power transmission, but i have no function generator or even a oscilloscope. Right now i'm searching for a variable 4MHz to 10MHz square wave generator schematic that would fit in, or any other oscillator that would work for this project. I was looking here: Square Wave Generator
Does anyone know if this is suitable for such frequencies?
Also, could someone more experienced than me draw a schematic for let's say a 10W or 20W output?
Or can i get any advice about this idea like what transistor to use on the output of the oscillator?

Thx in advance!

Dann

Hi Dann, I am waiting for some parts to arrive, I have some SG3525 chips coming that should work well, and will drive a mosfet directly or through a Mosfet driver, they are only capable of 0.4 Mhz though. When they arrive I will be designing a dedicated circuit for this which will have the option of an AC square wave or maybe 2 x 0.4 Mhz of DC pulses alternately which will be 0.8 Mhz I hope. If the chips do not arrive when I am ready, I will use the TL494 chips I have already.

The circuit will be PW and frequency adjustable with alternating pulses which can be utilised for driving a tranformer to make AC for a resonant Tank with the primary or the pulses summed to drive a DC resonant Tank for the primary.

I am hoping I can get the current sensing to work, to control the PW dynamically, if it is applicable.

I would prefer to use as simple a circuit as possible like the one I am using now. But simple has it's limits. So my goal is simplicity and effectiveness.

The transistor switch I am using is only rated to 100v it's a IRF540N but it is Neon protected which limits the switch voltage to about 80 volts. The circuit itself is only rated to 18 volts input but the coil can be supplied with up to 50 volts. The SG3525 chips can take 40 volts directly, as can the TL494.

As Cody said though the driving circuit can be anything really, the important thing is to wind the two transmitter/receivers well and this is the difficult part. Winding the coils require's patience and forethought so as not to end up with a big bunch of tangled wire. Some bee's wax is very usefull to make the winding surface tacky and to hold the windings for a rest. I wind all my coils by hand. I only made the surface tacky with wax for the first inch or so of the HV resonator coil former, when the first inch or so is wound the rest is easy to deal with. Make sure if you use wax that there are no big lumps or bumps just a thin smear, too much and it will end up on the outside of the coil and it won't be shiny and pretty.

I can provide the dimentions I wound mine to and the coil heights and stuff if needed but these things are never really final untill the last.

I have a feeling that big tall resonator coils "B" are not really necessary if the required capacitance could be acheived to lower the resonant frequency to below 500Khz. The peak voltage at my receiver output is about 5 to 6 x the input voltage. With bigger resonators it would be more. The higher the voltage the more reduction is needed at the receiver, but higher voltage will run different stuff. It is all relative to our needs or wants I think.

Cheers

[Farmhand]

DC Tesla Coil Design Link

Hi Cody, that link here you gave is very good, thank you for that. That explains it very well.
DC Tesla Coil design

I did notice that when I decreased the primary charge cap value too much that the switch got hot, likely because all the magnetic field energy from the charging inductor could not be stored in the cap and so was disapated as heat. However in my setup this now overflows through the choke which is in series with the charge battery and back to the source battery that way. I think another kind of resonance can be acheived this way if Identical batteries are used. I cannot quantify or validate that statement though.

That make's complete sense now. If the tank cap is too big the voltage will not double. This is a competely awesome situation of course and is one way to use the dead time to our advantage. Now I need to find a way to discharge two primary tank circuits through the one primary alternately, for double frequency, double voltage and quadruple power.

[Farmhand]

OK so this is the circuit I am using now to excite the transmitter.

http://wv0v9q.bay.livefilestore.com/...001.JPG?psid=1

I think i drew it correctly, maybe Cody could check it for me. The small cap I added to the variable cap is marked 682 so I think that is 6800pf and the variable cap is 40 to 1300 pf. I will get an acurate frequency and PW measurement, when I can, the switching waveform is very poor with the mosfet driver i have on this board there are resistors on the mosfet gate. So this could work much better with vertical switching waveforms. The switch trace is so bad there is not even one straight edge to it. This mosfet has been abused badly. I'll try the other fet. then add a turn off sharpener for now instead of the resistors.

It should look like this, But it doesn't.
http://koynpq.bay.livefilestore.com/...003.JPG?psid=1





Cheers

[cody]

Ok I see what you are doing with the recovery battery now. Thats a good idea. Im wondering if you might be able to get rid of the recovery and use something like a neon bulb across the transistor like a spark gap. That way instead of the field collapsing into the battery it would resonate within the tank across the spark gap after the transistor shuts off. Just a though, but may not work as well as what you have already. Be careful if you experiment with that idea, you might blow your transistor.

If we simply knew what the resonant frequency of your secondaries is we could easily calculate what the capacitance should be on you variable capacitor to be in tune.

Im not sure what your waveform is looking but most likely your transistor is putting out a square wave. However once you hook it up to the coil its not going to look like one, depending on where you have the scope hooked up. When in tune, when using square waves, across the coil the scope will see a perfect sine wave.

[cody]

Hey, try hooking up your scope across the capacitor in you circuit. See how high of a voltage its getting as your adjusting things.

[Farmhand]

Hey, try hooking up your scope across the capacitor in you circuit. See how high of a voltage its getting as your adjusting things.

OK no probs. Ahah ! Obviously this is my problem.

100 volts per division.
http://wv0v9q.bay.livefilestore.com/...001.JPG?psid=1

10 volts per division.
http://wv0v9q.bay.livefilestore.com/...002.JPG?psid=1

It appears as though the fist charge is missed and the second is hit TDC I don't know. indicated by the squigly top to the second oscilation.

What is you're evaluation of them.

Any way it gets originally charged to over 100 volts somehow or something it is a bit strange.



My de-Q-ing diode must be brned out from previous high current episode's.


..

[Farmhand]

And this is without the second battery. Not much changes when I adjust the cap except a small drop in amplitude with more capacitance.

http://wv0v9q.bay.livefilestore.com/...001.JPG?psid=1

I see so when the primary is in resonance the cap waveform will be all big one's. Awesome. looks like i gotta hit 250 Khz for that about, that is do-able.

Cheers

P.S. diode is OK.

[Farmhand]

40 volt primary cap charge ?

Hi Cody, I have four new cap charge waveforms can you tell me if any of them is heading in the right direction.

Cap charge -1
http://public.bay.livefilestore.com/...001.JPG?psid=1

Cap charge - 2
http://public.bay.livefilestore.com/...001.JPG?psid=1

Cap charge - 3
http://public.bay.livefilestore.com/...002.JPG?psid=1

Cap charge - 4
http://public.bay.livefilestore.com/...003.JPG?psid=1

So this is where I'm at so far, I made a base for the receiver and moved it 10 or 12 feet from the transmitter, it seems to work much the same as when next to the other one but an actual ground connection shared between them seems to drain the power.

With all of those cap charge's I get between 40 to 70 volts on the receiver output but the frequency is different.. The LED lights quite brightly and I managed to find another 5mm white LED, but it blew too so I still only have one working white LED, it must be a good one.

Cheers

[MonsieurM]

I know some of you don't have and are looking to buy an affordable oscilloscope, I found this, it actually is an oscilloscope/function generator:

VELLEMAN Sa PCSGU250 USB PC Oscilloscope with Function Generator



I hope you find this useful

ps: Farmhand, the set up is looking good

[Farmhand]

Alrighty I been playin around and I get pretty good results with a bigger cap on the primary charging circuit, i'm using 0.47uf now and that work's good for lower frequencies up to about 18Khz with 6.6us ( more like 8us ). It uses about 170 Ma to 200 Ma but when a load is applied to the receiver the input current rises a bit and if I light a couple of neons on the transmitter top the input rises a bit more but the LED on the receiver stays lit even if I touch the toroids for a while. I can only drop the voltage to 35 volts or so now by touching the top, then it starts rising slowly charging me up.

Here is some piccies.

This is the pulse to the mosfet gate.
http://public.bay.livefilestore.com/...003.JPG?psid=1

http://public.bay.livefilestore.com/...004.JPG?psid=1

I glued three of these caps together and soldered them in series to get different values to try.
http://public.bay.livefilestore.com/...005.JPG?psid=1

This is the cap charge, frequency reading too.
http://public.bay.livefilestore.com/...002.JPG?psid=1

Dodgy old circuit i'm using and the recovery choke.
http://public.bay.livefilestore.com/...007.JPG?psid=1

This is the charging inductor, i think it is about 110 turns on a 10mm x 40mm iron powder core, a ferrite will work too I think.
http://public.bay.livefilestore.com/...006.JPG?psid=1

And here is the receiver over on the other wall, about 10 feet away is all and I have a wire in place of the ground.
http://public.bay.livefilestore.com/...008.JPG?psid=1

Oh yeah I measured 30 Ma of current flowing through the LED.

And here is the revised circuit as I am using it now.
http://public.bay.livefilestore.com/...001.JPG?psid=1

And a link to some Tesla Autobiography thingy. It's a good read.

My Inventions: The Autobiography of Nikola Tesla

Chapter 6—The Magnifying Transmitter

My Inventions - Chapter 6—The Magnifying Transmitter

Cheers

P.S No probs monsieur, thanks for the inspiration, it is very interesting and amazing, it will be fun to start using higher voltage's. I like a bit of a charge up sometime's.

[Farmhand]

Well well, now this is wild , it can kinda light CFL's from the transmitter top while just dimming the LED. I didn't expect that. Should be only a couple of hundred volts there. Maybe it's normal. Bit more power and it will work from the receiver too.

touching the side.
http://wv0v9q.bay.livefilestore.com/...003.JPG?psid=1

touching the top
http://wv0v9q.bay.livefilestore.com/...001.JPG?psid=1

I'm impressed, this is still only running from 12 volts at 180 Ma. I could tripple the power input to the transmitter so the cfl would light better and still be using less than half the cfl's rated power consumption it's a 15 watt cfl.

A funny thing happens when the cfl is touched on there. The input cuurent goes down then up and repeats this when I remove it, like surging or backwash.

Cheers

[Farmhand]

I have a funny feeling that if I take this transformer and connect one end of the scondary to ground and the other end to an antenna it will also function as a transmitter to a degree, but it only has a 1 - 3 step up. Maybe I'll mess around with that idea later.

http://public.bay.livefilestore.com/...003.JPG?psid=1

Here is a Tesla Screen Saver, it's pretty neat. I can't remember where I got it so it can be downloaded from this link.
tesla.zip - Windows Live

Cheers

[Farmhand]

OK I had some better results, for a while before I decided to improve my gate drive ( the IC was damaged ) after getting a nice square drive signal the circuit became very efficient but when i went for more power the mosfet failed. I had to remove the protection neon because it was glowing purple.

I guess I pushed it too far. More abrupt switching caused an awefull lot of voltage at the primary cap with less than 0.3 uf. When I go above 250 Ma on the input everything lights up good but the mosfet gets really hot. I'm trying to work out what I'm doing wrong.

Here is some pics before I screwed the power up and fried the fet.
http://wv0v9q.bay.livefilestore.com/...009.JPG?psid=1

Cfl connected to top and ground.
http://wv0v9q.bay.livefilestore.com/...007.JPG?psid=1

It can light two neons in series by holding one leg and touching the other to the top. It burns my finger after a bit.
http://wv0v9q.bay.livefilestore.com/...013.JPG?psid=1

And it will light up a 5mm LED on the receiver across the room trough a FWBR and 270 Ohm resistor.
http://wv0v9q.bay.livefilestore.com/...015.JPG?psid=1

I have parts and am designing a new circuit to drive the mosfet's, I might try to use two alternately to reduce the stress on them. Not sure yet what I will come up with.

I think the noise from the transmitter affect's the circuit at a certain point and causes erratic behavior and double pulsing, like this.
http://wv0v9q.bay.livefilestore.com/...004.JPG?psid=1

Sketch pad and Breadboard time.

Cheers