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Author Topic: Magnetic Resonance Devices based on Don Smith Concepts  (Read 453343 times)

xee2

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #195 on: September 05, 2009, 04:11:59 PM »
@ stprue

No I wanted something accurate so I bought one.  Here is the link!  Lots of good stuff here but not always the cheapest.

http://www.amazing1.com/sparkgap.htm

Great find. Thanks for the info.


stprue

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #196 on: September 05, 2009, 04:18:12 PM »
@ stprue

Great find. Thanks for the info.

No problem xee.  If you are working with lower voltages the spark gap will be very close and something precise really helps out! 

stprue

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Yucca

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #198 on: September 05, 2009, 05:01:33 PM »
Here is the little driver and it's worth the $4.95 

http://www.goldmine-elec-products.com/prodinfo.asp?number=G16565

I through this together quick but the neon won't light unless I'm touching it, it is reaching with me, so the more surface area of my fingers that are touching it the more it lights up.  It will also light if touch the caps as well and if I remove the red hiarpin wire it stays lit fully....I can actually see little electrical sparks inside it.  I haven't noticed this but after my spark gap is put together it will be a lot easier to test stuff.  Right now it's just placed by hand.

I wish I had a scope.
Hi sptrue

You inspired me to try a hairpin on my protoboard last night. My caps were too big to get a small wire going. So just for kicks I threw a 22 turn toroid choke accross it instead of a hairpin wire. It is wound with twincore bellwire which has a shield layer of aluminium foil around it.

I gave my HV module 6V it took 180mA (so about 1W).

After running and playing with it for maybe ten minutes I noticed that the whole choke heated to quite warm to the touch, this level of heating was suprising as the choke has quite a mass it´s about 3CM diam. I may try some rough calorimetry on it. Every other component in HV module and also the hairpin caps remained at room temp thereabouts.

I also tried using the secondary choke wind to draw power off and lit a neon real bright and as you say through the bright orange glow I could see pinhead sized violet discharges dancing over the surface of each electrode.

I also tried a 1ohm 5W resistor across instead of hairpin wire. Using my scope I worked out the average power showing across it, it came out at close to 10W, I was extatic COP10 :o until I realised all of the power was seen in a 5MHz ringdown because the resistor has inductance to it and so the power factor of this oscillation would be very low :(

edit:
I´ve no doubt you´ll end up getting a scope in the end. If you live in the states then you should start keeping your eye on 2nd hand tektronix (or other qual brand) scopes on ebay. Not with a view to buy right away per-se but sometimes you get a real bargain passing through, especially if youre only after analog. I find when the auction ends at an ungodly hour less people are awake to battle at the end.

stprue

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #199 on: September 05, 2009, 05:45:34 PM »
Hi sptrue

You inspired me to try a hairpin on my protoboard last night. My caps were too big to get a small wire going. So just for kicks I threw a 22 turn toroid choke accross it instead of a hairpin wire. It is wound with twincore bellwire which has a shield layer of aluminium foil around it.

I gave my HV module 6V it took 180mA (so about 1W).

After running and playing with it for maybe ten minutes I noticed that the whole choke heated to quite warm to the touch, this level of heating was suprising as the choke has quite a mass it´s about 3CM diam. I may try some rough calorimetry on it. Every other component in HV module and also the hairpin caps remained at room temp thereabouts.

I also tried using the secondary choke wind to draw power off and lit a neon real bright and as you say through the bright orange glow I could see pinhead sized violet discharges dancing over the surface of each electrode.

I also tried a 1ohm 5W resistor across instead of hairpin wire. Using my scope I worked out the average power showing across it, it came out at close to 10W, I was extatic COP10 :o until I realised all of the power was seen in a 5MHz ringdown because the resistor has inductance to it and so the power factor of this oscillation would be very low :(

edit:
I´ve no doubt you´ll end up getting a scope in the end. If you live in the states then you should start keeping your eye on 2nd hand tektronix (or other qual brand) scopes on ebay. Not with a view to buy right away per-se but sometimes you get a real bargain passing through, especially if youre only after analog. I find when the auction ends at an ungodly hour less people are awake to battle at the end.

I will get a scope some day.

Your tests sound pretty interesting.  I'm still working out how the led on my other circuit is lighting but it looks like it has something to do with the + rail and a few other factors.  Anyway I will figure it out!!! 

Instead of a choke try a power inductor like in my pic.  It works ok. I think the radiant event is taking place off the tungsten electrodes so that is where I think it could be captured.....maybe  ;D

Yucca

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #200 on: September 05, 2009, 06:37:06 PM »
I will get a scope some day.

Your tests sound pretty interesting.  I'm still working out how the led on my other circuit is lighting but it looks like it has something to do with the + rail and a few other factors.  Anyway I will figure it out!!! 

Instead of a choke try a power inductor like in my pic.  It works ok. I think the radiant event is taking place off the tungsten electrodes so that is where I think it could be captured.....maybe  ;D

At such high freqs your protoboard rails can couple quite effectively to the source oscillation, the magical world of RF... :) I would imagine you could tune the LED brightness by moving a small shunt up or down the power rails to tune for resonance.

stprue

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #201 on: September 05, 2009, 08:45:11 PM »
At such high freqs your protoboard rails can couple quite effectively to the source oscillation, the magical world of RF... :) I would imagine you could tune the LED brightness by moving a small shunt up or down the power rails to tune for resonance.

That is a good idea but not for this set up.  I already tried to no avail.  It is using part of my JT and/or part of my +probe of my DMM even when it is off.  I will do some more tests Sunday or Monday when I have some time.

Yucca

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #202 on: September 05, 2009, 11:13:49 PM »
Yucca
yer it was air, i didn't realize they had a top freq, it's amazing how much we need to know when building this stuff, a fantastic way of learning anyway.

Wow just looked up Vacuum caps they look amazing, how do you adjust them?

Edit OH i see they still have an adjuster, i guess you fit a knob to the shaft


JENNINGS TECHNOLOGY COMPANY VACUUM VARIABLE CAPACITOR
• PN: CMV1-1000 - 0103 • Capacity Range: 8 - 1000pF
• Voltage (KV) Peak Test 3KV Test 3KV Working
• Current Amps (RMS) Max. 40A
• Type: Ceramic • Length: 4.33”
• Diam: 1.78” • Capacity vs Turns 10t = 8pF   0t = 1000pF
• Drive on TOP: Please Note, this is not ¼" Shaft, but a special "Spline" Cog Type Drive!! Click for large photo
• Frequency: 2 - 30MHz
• Brand New Item / Never been used. Unusual and very hard to find!
• Price:£125 (5pcs available) Click for large photo

I checked out the site, that looks like a good vac cap at a fair price, 1000pF is nice and high, 3kV sounds low but should be enough for this particular device judging by Dons gap width. I'm not sure what happens if you overvolt vacuum caps, do they just arc, does a conducting plasma begin to form, do the copper cap plates get pitted or otherwise damaged? Maybe a plasma glow develops because I often see them made with clear glass envelopes, perhaps for eyeballing when running?

Maybe on this device we could get away with air caps, they only drop off when you drive them hard, for high impedance work they should get to much higher freqs. But I suppose in this case we will be driving it pretty hard and wanting a fast powerful impulse and large amplitude ring when the gap fires, perhaps a high power rated aircap would suffice if we were running at say 0.1 of its power rating? But then that would be big and pricey too. hmmm...

Paul-R

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #203 on: September 06, 2009, 03:32:50 PM »

I wish I had a scope.

Why not go back to your old school and talk to your Head of Physics?
You might be able to start up a dialogue, and maybe bring your
rig in and test it on their premises.

Alternatively, you could ring up the Group Chief Accountant of any very
large firm, possibly British Telecom, and ask them if they will give you
one (They say "Yes" more often than one would think):
British Telecommunications plc
81 Newgate Street
London
EC1A 7AJ
This number may not be right, but you should ask for the correct one:
Tel: 020 7356 4894 (international: +44 20 7356 4894)

Paul-R

p.s. I suggest the chief accountant because they often have a very boring
life, and your intervention may be the most fun they have had for years.


allcanadian

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #204 on: September 06, 2009, 04:39:45 PM »
@stprue
Quote
I wish I had a scope.
Another option is to get your hands on an old CRT computer monitor or small television that everyone is throwing away these days, the premise of a crt is that an electron beam is deflected by a magnetic field. A mosfet gate is voltage driven which can be used to drive the deflection coils. A mosfet/555 can be used to drive the horizontal deflection coils and a mosfet on the vertical deflection coils will convert a voltage potential to a proportional current in the coils. It is a cheap alternative if you are playing with HV fields which tend to destroy oscilloscopes.
Regards
AC

Yucca

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #205 on: September 08, 2009, 02:19:05 AM »
@stprueAnother option is to get your hands on an old CRT computer monitor or small television that everyone is throwing away these days, the premise of a crt is that an electron beam is deflected by a magnetic field. A mosfet gate is voltage driven which can be used to drive the deflection coils. A mosfet/555 can be used to drive the horizontal deflection coils and a mosfet on the vertical deflection coils will convert a voltage potential to a proportional current in the coils. It is a cheap alternative if you are playing with HV fields which tend to destroy oscilloscopes.
Regards
AC

Lol, my first scope was using my black and white TV twenty odd years ago. I used the existing TV vertical drive circuit to drive horiz yolk coils at about 29KHz scan freq. I drove the vertical yolk coils from an audio amp. No trigger made it all but unusable but it was cool watching music on it. I actually installed a DPDT toggle switch and a jack socket so I could switch my TV to scope mode and play my radio or tape player through it.


Speaking of scopes and music, this is a very cool X/Y vector encoded demo being viewed on an analog scope:

http://www.youtube.com/watch?v=s1eNjUgaB-g

if you have a 2ch analog scope with X/Y mode then try it yourself by putting probes across your computers audio output. When you run it you can observe the clarity of your computers audio amp, mines pretty poor and muddy.

The youtube info text contains a link to the waveforms to use in FLAC or WAV format.
« Last Edit: September 08, 2009, 02:56:49 AM by Yucca »

flathunter

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #206 on: September 08, 2009, 10:31:33 AM »
I gotta respect you builders on OU.com.  Using the insides of a TV as a scope??  Now that really is hardcore, A Team style  ;D

Keep up the good work!  I'm too busy for any more Tesla fun, but when i finally raise the cash to move into a place with some space for the little one as well as my T.Coil, i'll be joining you.  Till then I am following every word with great interest.....
« Last Edit: September 08, 2009, 06:06:04 PM by flathunter »

stprue

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #207 on: September 08, 2009, 04:05:52 PM »
Why not go back to your old school and talk to your Head of Physics?
You might be able to start up a dialogue, and maybe bring your
rig in and test it on their premises.

Alternatively, you could ring up the Group Chief Accountant of any very
large firm, possibly British Telecom, and ask them if they will give you
one (They say "Yes" more often than one would think):
British Telecommunications plc
81 Newgate Street
London
EC1A 7AJ
This number may not be right, but you should ask for the correct one:
Tel: 020 7356 4894 (international: +44 20 7356 4894)

Paul-R

p.s. I suggest the chief accountant because they often have a very boring
life, and your intervention may be the most fun they have had for years.

That's good info, thank you kindly!

stprue

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #208 on: September 08, 2009, 04:07:25 PM »
@stprueAnother option is to get your hands on an old CRT computer monitor or small television that everyone is throwing away these days, the premise of a crt is that an electron beam is deflected by a magnetic field. A mosfet gate is voltage driven which can be used to drive the deflection coils. A mosfet/555 can be used to drive the horizontal deflection coils and a mosfet on the vertical deflection coils will convert a voltage potential to a proportional current in the coils. It is a cheap alternative if you are playing with HV fields which tend to destroy oscilloscopes.
Regards
AC

Doesn't sound to impossible to do!  thanks.

Yucca

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Re: Magnetic Resonance Devices based on Don Smith Concepts
« Reply #209 on: September 08, 2009, 05:49:05 PM »
@All,

I'm going to wind another 24 turn secondary identical to the one I've already wound and then join the two secondaries together to yield a 48 turn split coil. I will make the joiner be adjustable so I can try different coil spacings.

I've also realised that at these frequencies you need to keep wires straight and fairly rigid because movement of wires changes L and wires getting too close changes C and so it doesn't stay in tune.

@Peter, your build is looking nice and rigid just like Dons did, this is important for ease of tuning.

My new coil will also be mounted on its side and I will move the primary cap and gap onto the coil board so the connections between them and L1 stay the same. I will use single cored copper wire with PVC insulation, like used in house wiring.

Thinking more about Dons table top device: it may be in effect a 3 coil device. 1 primary coil and two identical 1:1 coupled secondaries. The magic might happen between the two secondaries as peter has been speculating already.

One thing that bothers me is that the only tuning point we see on Dons device is the slidable L1. To tune a device like this I would think we would need variable C1 to tune L1 to L2/L3. Don seemed to have hit the sweet spot with two standard value C1s and integer turn L1. Was he lucky? In these aircoils the Q is quite narrow and peaky.

The only thing that might make me less suspicious is if the secondary end variable  resistor to ground enables one to tune L2/L3 half wave resonance precisely? I don't know yet because I havent established half wave resonance yet with nodes on the ends and antinode in centre tap.

I have just noticed a few 1kV caps of different values on some TV boards I have shelved, and I will desolder them later today. They should be OK provided my primary gap is kept at say 0.5mm or less.

Also I've just realised my bridge diodes have a minimum response time of 100nS (for some reason I thought it was 10nS). So I'm thinking that the max freq sin I can rectify is 10MHz. That's worrying because the natural 0.25 wave resonance freq of my 24 turn coil is about 16MHz, that means half wave resonance of a similar 48 turn coil would also be about 16MHz. Will faster diodes be needed? maybe.