Hey, I just wanted to make an observation about the wire guages you are using because I think this is VERY important in how these coils interact with each other. Just like length of coil, number of turns, etc...
14AWG conductor diameter in inches: 0.0641
20AWG conductor diamer in inches: 0.032
Notice anything?
So if we take that idea and apply it to a smaller size wize:
24AWG: 0.0201
30AWG: 0.01
Any thoughts?
PC
EDIT: Yes, I understand the smaller wire can't handle as many amps.

...

My large aircore uses 18 awg secondary and 12 awg insulated stranded primary.  120:1200 turns.

That is impressive, Lynx.

  As we have discussed, measuring output-power can be tricky from a device such as this, and a simple water calorimeter was suggested by Chet and me.

To follow up on this idea, I've done a short vid this morning -- which shows a very simple water calorimeter and how I tested that it can quite useful and reliable:

http://www.youtube.com/watch?v=4ICpD37usIE&feature=youtu.be

One needs to be able to operate the device with the output power going into a simple resistance, and I think we're approaching this point.

The text:
Today I set up a simple water calorimeter, to measure output energy and power with decent accuracy.  I have other calorimeters, but this is to show how straightforward it is, and to allow the experimenter to get a handle on output power -- which can often be tricky with output that is far from DC or sinusoidal AC; for example, from a blocking oscillator or Don Smith-type device.   


   Water is weighed in grams with a scale that cost about $10 and placed in a styrofoam cup.  Or you could use a graduated cylinder, 1ml = 1gram for water. Temperature change (delta-T) is measured in Centigrade using a TK thermometer, that cost about $10 also.  For this check, I used a power supply to give me 14 V and measure the current; I could have used a battery at 12 V (for example) and an ammeter.

The power is dumped into an "immersion heater" (about $7) which is simply a resistive coil; this is stirred in the water to heat the volume of water.  At room temp, the resistance was 53 ohms.  Time is measured with a stop-watch on my wrist.  Easy.

Result:
Power-input = 14V @ 0.264A = 3.7 Watts input.
Energy output = Qheating = 4.19 J/g-degC (H2Omass) (delta-TempC) =
   4.19 x 316g x 0.9C = 1192J
This heating required 5min19s = 319 seconds, so the output power measured in the calorimeter is:
Poutput = Eoutput/Time = 1192J/319sec = 3.7Watts -- which agrees very well with the input power.

Thus, we have tested the simple water calorimeter and shown that it WORKS!  It is a valuable tool for measuring output energy and power.

In another test, I ran at 12V @226mA = 2.7W and the water heated from 21.2 to 21.6 Degrees-C in 210S.  So
Eout = 4.19 (316g) 0.4C = 531J, and the power-out is
Pout = 531J/210s = 2.5W, compared to the known 2.7W in. 
To get decent accuracy, one needs to run for a long enough time to heat the water by nearly 1deg-C or so.

Hi Lynx Lampistes, Physics Profs, Joule Robbers, NRG Hunters, Witty Experimenters,
Skeptics, Trolls and my Sister in Law (for ex.)

Sorry for disturbing.

With my (near botched) Lynx Joule Lamp, I'm not (still?) able to run any of these led bulbs.
Just bl' blinkings observed. I'm not interested in these deadly CFLs (and vaccines, BTW)

I have made another primary coil (I mean: the one with less turns) with about twice more turns.
Now I'm drawing about 100 ma (under 12 volts). (VS about 400 ma with my previous primary coil).
I'm definitely more confident with my small fluorescents tubes.

I have noticed that the brightness of these tubes seems not depending upon their
"Watts" but upon their Lenghts!

4 Watts: length 136 mm
6 Watts: length 212 mm
8 Watts: length 288 mm
(Diameter 16 mm)
My 'secondary' coil length is about 230 mm.

A 8 watts bulb 'looks' more efficient than a 6 watts one.
These 4 watts tubes are definitely useless as they refuse to give obvious lights!

IMO, this fluorescent tube just act as a kinda antenna.
It also likes (= needs)  to be placed parallel to the coils.
BTW: I use only one wire.
You add another fluorescent tube. You do not not draw much amp.
It also seems that you gain some more luxs.
Now! using any 'light box' (= a kinda Faraday cage) could be not so evident. But might be done.

In the same vein, and In My Poor Bloody Froggy Opinion (IMYPOBLOFO), trying to measure
-if it is the case-  and -as far as I can catch it- any output of such a LJL device with calorimetry
seems not so appropriate.

Gwella gourhemennou a-berz Jean.

That's interesting and quite by accident that the copper portion of the wire diameter is double. 

I am attaching a drawing that might help some of you convert your LJL to this newer version.  Hopefully you can unwind the secondary onto a spool, reconfigure and try this latest setup.  You don't need the PVC end caps, nor do you need the switches.  Basically its just the coil tube and wiring to the transistor and LED bulbs.  This circuit design will light LED bulbs very brightly, or you can dim them at 50% power.

Hopefully someone will try this on bamboo for a cool tropical look!  Sort of a Gilligan version.

Hi LYnxsteam

Thank you for shearing your interesting video and schematic  ,interesting setup you have on the final one the small
Version, the  large  version need expensive wire (12#AWG)but this one is cool  but I have a couple question :
First I couldn't find PVC with same diameter can I use a little bit larger diameter .
Second we don't use in Europe 120v so all the LEDs we have are 220v will these LEDs work with this circuit .

Thank you in advance

Ehsan

Ehsan -- the bulbs I'm using here with Lynxsteam's build are actually 220V LED bulbs!  and they work just fine, better than any 120V LED bulb I've tried in fact. 
The particular bulbs I'm using most -- not that you should necessarily use the same bulbs -- are these (shown below).

Also, "First I couldn't find PVC with same diameter can I use a little bit larger diameter ."  That should not make much difference IMHO.

I have made three sizes of these.  Each diameter is double the next.  3/4" D, 1.5" D and 3" D.  Each has a length about double the other.  What you make will depend on how many bulbs you want to run, and what materials you may have handy.  They all work very well.  Larger LJL Aircores have more capacity and can handle more bulbs.
The medium sized LJL is a nice size, not too big, and can handle at least a room of light.  The larger version can handle several rooms, whereas the small version can handle 4-6 bulbs.

Here is Part 1 of the "How To" series on making these AirCores.  Part 2 will cover wiring the circuit and testing.

http://youtu.be/3C-WW9gd8SM

Ehsan -- the bulbs I'm using here with Lynxsteam's build are actually 220V LED bulbs!  and they work just fine, better than any 120V LED bulb I've tried in fact. 
The particular bulbs I'm using most -- not that you should necessarily use the same bulbs -- are these (shown below).

Also, "First I couldn't find PVC with same diameter can I use a little bit larger diameter ."  That should not make much difference IMHO.

Hi JouleSeeker


Thank you,  its good for these coils to work on this wide of range of voltage 120-220v.


Ehsan