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Author Topic: Lasersaber strikes again. A joule thief king ?  (Read 412366 times)

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #240 on: June 20, 2014, 08:43:21 AM »
Hi TinselKoala,
In your video clip, I saw had a ferrite core horizontal oscillations-holding television old. . .
Difficult I found, that can replace the coil with others? . . .

Thanks

The coil is a "loopstick variable inductor". I see that they are getting hard to find. I guess I'm going to have to visit my supplier tomorrow and buy out his stock!

But I think you can make your own. Just take a piece of ferrite for the core, and wind around 100-200 turns of Litz wire on it to make around 9 milliHenry inductance, for the innermost coil. This will be the one with the LEDs across it. Then wind another coil of a single layer of thicker magnet wire on top of that, 20 turns. This is the "magic" coil that does the interesting things. I think it needs to be connected "backwards" in the schematic. Then on top of the whole thing wind another 100 turns or so of thinner magnet wire. This is the coil that is connected to the Collector on one end and the Base Resistor and the Cap (or other supply) + on the other end. 
I think this should work, if you can't find an actual loopstick. If you can figure out some way to pull your ferrite core in and out of the coils, all the better.


TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #241 on: June 20, 2014, 08:50:01 AM »

havuhung

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #242 on: June 20, 2014, 09:04:15 AM »
Hi TinselKoala,
yes, I will try to test with a small piece of ferrite rod and can be moved in a paper tube.

Thank you

Acca

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #243 on: June 20, 2014, 10:33:58 AM »
 Off topic about radio signal amplification using a ferrite loop antenna…
 
Quote
TinselKoala
Quote

If you are not familiar with the russian ferrite rods they are very inexpensive  from
the UK..  first link below..
 
 
Loop antenna is strange….ferrite rod is ???
 
"How can it be stated that an already radiated electromagnetic 'wave' propagates
with an associated transverse magnetic 'field', when electromagnetic radiation is
know to not be a stream of electrons (current) travelling at the speed of light,
whilst additionally, at no point along the 'wave' is there any circuit through which
charge can circulate or flow in order to generate a magnetic field?"
 
answer ? below:
 
"Thus the ferrite rod has never been the 'antenna' energising the coil, because it
has always been the antenna coil energising the ferrite rod! 
Electromagnetically radiated radio-frequency photons energise electrons within
the coil;  electron activity constitutes circular charge flow around the coil;  this
generates an alternating electro-magnetic field within the ferrite rod;  which
subsequently energises and aligns the unpaired electron spin gyros within the
ferrite.  Hence a ferrite rod does no more than concentrate the alternating
magnetic field, as generated by photon induced electron flow within the coil, into
aligned electron spins within the ferrite, and via its concentrating permeability, 'Q'
magnifies the voltage transduced by the coil with an improved circuit efficiency
through phase shifted oscillation of resonant energy exchange . "
 
 
"extracted and written by Graham Maynard, of UK"
 
http://www.rapidonline.com/Electrical-Power/100mm-Ferrite-Rod-Aerial-88-3098
 
http://www.zen22142.zen.co.uk/Media/fsi.htm
 
http://www.youtube.com/watch?v=iqYZcRXCGxM
 
 http://www.youtube.com/watch?v=qWSqvb9NdLo[/font][/font]

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #244 on: June 20, 2014, 05:17:44 PM »
That's pretty neat, but also pretty expensive and heavy.

I've been using a "slinky" spring toy thing for an antenna for my Australia Radio crystal set. It works great! And it's 'tunable' by how much you stretch it out.



Pirate88179

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #245 on: June 21, 2014, 04:32:01 AM »
That's pretty neat, but also pretty expensive and heavy.

I've been using a "slinky" spring toy thing for an antenna for my Australia Radio crystal set. It works great! And it's 'tunable' by how much you stretch it out.

A slinky?  What a brilliant invention (yet another device that was discovered by accident while attempting to make something else) and also, what a brilliant new use for it.  Tunable too....excellent!  Great thinking over there.

Bill

Farmhand

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #246 on: June 21, 2014, 06:22:02 AM »
Well the difference in transistors and their drive requirements makes a big difference to running down a cap. I'm working on a single coil circuit to rival the performance of This Super Looper circuit, still not sure where the looper part comes from, But anyway just the difference between the power draw when using an MPSA06 as compared to an MPSA18 is huge in this low power scale. I noticed the MPSA18 transistor doesn't draw down the drive pulse as much as the MPSA06 Could the base of the MPSA18 allow less current to pass and still work well ? And could this be why one transistor gives better efficiency results at lower voltages than another ?

..

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #247 on: June 21, 2014, 06:43:51 AM »
@Bill: I can't really claim originality for the "slinky antenna" idea. I can't even remember when I first used one for that purpose! But about 15 years ago I made a great electrostatic voltmeter out of a Slinky, taking advantage of the like-charge repulsion effect. Dangle the slinky inside a big transparent plastic tube, with a little weight on the bottom of the spring and connect the HV source to the top. The slinky will stretch more and more as the applied voltage goes up.

@Farmhand:
I tried MPSA18 and it results in a slightly dimmer LED stack, a bit slower discharge rate, but the LEDs go out at a slightly higher voltage than they did with the 2sc3198.

Here's the thing running on a "radio shack" photovoltaic cell:

http://www.youtube.com/watch?v=BHI7LnVWBlY

(I just realized I've had that red MagLite for 30 years.)

Farmhand

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #248 on: June 21, 2014, 08:32:19 AM »
Time fly's hey, Good job with the loopstick. I am seeing similar results with the MPSA18, the LED gets dimmer as the voltage drops and the lower the voltage drops the less is the power draw, so the lower the voltage goes the longer it runs, takes too long to wait for my 25 Farads to drop under 0.6 volts, it just keeps dropping slower and continues to run.

..

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #249 on: June 22, 2014, 12:38:31 AM »
You could put a pushbutton and discharge resistor (one or two ohms) across the capacitor. That way you can take it down to whatever voltage you want to be looking at.


I have some interesting transistor data on my SooperLooper low-voltage version of the LaserSaber circuit. As I showed in the last video, the thing starts at a higher voltage just above 0.4 volts and runs down to something around 0.12 volts. That's using the 2sc3198 transistor.

Without making any changes in the circuit or tuning, and using the PV cell and flashlight as the power source, I've tested 4 transistors.

MPSA18 Start: 0.430 V   End: 0.123 V
2sc3198 Start: 0.443 V   End: 0.111 V
BC337-25 Start: 0.409 V   End: 0.104 V

--and the Low Voltage Winner (a real surprise)---

2n2222a Start: 0.420 V  End 0.102 V


I'm defining "end" as the minimum voltage at which I can barely see a glow in all three LEDs, sustained by carefully shining the flashlight partially onto the PV cell.

I think the longest run in terms of time is given by the 2sc3198, probably because of the higher initial charge voltage at Start.


Another interesting feature of this circuit.... when I break the connection to the LEDs, the voltage behaviour is just the same. That is, it seems to start, run and stop at the same voltages, judging by the voltmeter, even when there is "no load" and the LED connection is open. I think that's really weird. Steorn would probably say that this indicates OU performance, since the LED light is evidently coming for free.

 ;)

(ETA: I went out and bought four more loopsticks yesterday.)

ETA2: the corrected schematic:

d3x0r

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #250 on: June 22, 2014, 12:46:47 AM »

Another interesting feature of this circuit.... when I break the connection to the LEDs, the voltage behaviour is just the same. That is, it seems to start, run and stop at the same voltages, judging by the voltmeter, even when there is "no load" and the LED connection is open. I think that's really weird. Steorn would probably say that this indicates OU performance, since the LED light is evidently coming for free.

 ;)

(ETA: I went out and bought four more loopsticks yesterday.)

ETA2: the corrected schematic:
to be clear.... "the voltage behavior is the same' across the same time span?  or just the high/low character?

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #251 on: June 22, 2014, 12:52:34 AM »
to be clear.... "the voltage behavior is the same' across the same time span?  or just the high/low character?

I mean the high-low behaviour, and the seeming rate of discharge during the "run" phase and after "end" (since there is no load I just am looking at the voltmeter).
I have no solid data on the time span... yet. To log it properly I'll have to rig up an Arduino based timer-logger, or see if I can wire together some other test equipment to get accurate timings.
I think I can get times to the fraction of a millisecond, maybe even microsecond, using Arduino and triggering on the light of the LEDs with a proper sensor. This will take a day or two for me to get it together though.

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #252 on: June 22, 2014, 01:38:09 AM »
Here's how to make the coil.

1. Stock loopstick variable inductor. The windings are in series, so it's really just one winding. Note the herringbone-weave winding of the fine Litz wire.

2. Two layers of cloth athletic tape, just to make a surface for the next winding.

3. 20 turns in one layer of #23 magnet wire, secured with a layer of heat-shrink tubing (or epoxy on my first coil).

4. 100 turns of #32 magnet wire, secured with another layer of heat-shrink tubing.

conradelektro

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #253 on: June 23, 2014, 11:37:53 AM »

(ETA: I went out and bought four more loopsticks yesterday.)


@TinselKoala: what was the original purpose of these "loopstick" coils? It looks like they were used in old radios?

It is interesting that the loopstick coil has two windings?

Greetings, Conrad

P.S.: I found the answer: http://en.wikipedia.org/wiki/Loop_antenna


TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #254 on: June 23, 2014, 03:42:21 PM »
Yes, the ferrite loopstick antenna can be found in just about every AM radio, and the loopstick variable inductor can certainly be used as an antenna in some cases, as I showed in the "electrosmog harvester". But that's not the primary purpose of the variable inductor type. They are used in antenna tuning / matching circuits in multi-band radios or other places where a variable inductor handling high frequencies is needed. (not UHF, just "HF", ten meters and longer)

The Litz wire winding and the herringbone winding / weaving pattern help with the overall efficiency of the loopstick variable inductor. It's interesting to compare the herringbone pattern with coils that use "caduceus windings". The herringbone has the same kind of crossing angles although at less than 90 degrees.

The little metal clip on one end is made to go through a hole in the chassis and then you have the screwdriver slot in the shaft so the inductor can be precisely tuned. These that I have can be varied from about  1-2 mH to about 9-10 mH.

There are two coil windings but really it's a single coil, the two windings are in strict series and in the same direction, the end of one on the outside goes to the start of the next one on the inside. I don't know why these have two winding groups, perhaps for cooling purposes or to get the herringbone geometry right. They are more complex than they seem at first glance, being very carefully constructed using the fine cotton-covered Litz wire and the herringbone weave.

The antenna article was very informative, thanks for linking it.


ETA: Here's a pretty fancy, modern, loopstick antenna:
http://www.palstar.com/en/la30/

ETA2: You've got me looking now. Here's an interesting thread talking about loopstick variable inductors and crystal sets:
http://theradioboard.com/rb/viewtopic.php?t=3777

http://home.earthlink.net/~kd7tog/Loopsticks/RRCoils.PNG

http://home.earthlink.net/~kd7tog/Loopsticks/MiscCoils.PNG