Big Joule Theif

[SkyWatcher]

lighting dead bulbs

Hi again folks, I was wondering if anyone noticed if the joule thief with typical bifilar wind and secondary high voltage pickup was able to light damaged filament fluoro's as well. I'm currently winding that type because what I've been testing with is the bifilar choke config. with secondary wrapped on outside which I don't think is as efficient. Though also wondering has anyone tried the standard type coil configuration with high voltage secondary pickup wound on a ferrite rod core first then the bifilar JT wind on outside, let me know please. Thanks
peace love light
Tyson

[Lidmotor]

The Halo Light

Hi folks, I would like to thank Lidmotor and whoever else for throwing out the idea of using the halo type bulb which I happen to have an older one in my work light, it really pumps out the light with a joule thief circuit with high turn secondary of 24 guage wrapped around. Also works well with a regular small 120V to 12V trafo. wired in a step-up configuration pulsed with 555 at 12V. I notice also with the halo bulb that with the high voltage wires it is sensitive to which way they are connected to bulb, if connected one way it causes a purple glow on one side and a rotating light effect in one spot, however when swapping the connection it lights normally, strange considering its ac off the secondary. And when the elements go bad i can use an ignition coil to light it. Thanks.
peace love light
Tyson

@ All I am currently using the "Halo Light" on my boat for off shore lighting. The round Fl really fills an area with light like Skywatcher said. It simply gets the job done and I rely on it. I'm glad that other people are finding out about it. I am currently working on the SEC project (High voltage from thin air) and trying to figure out a way to get that round FL bulb to "pop" onto that high bright illimination off the SEC. So far no luck there. The SEC seems to really like LEDs instead.

Lidmotor

[SkyWatcher]

Hi Lidmotor, thanks for reply. I tested the inverted JF circuit with the 555 timer varying the on time of the joule thief and it improved things a bit with some less heating in transistor. However, so far the best setup I have tested is using a 555 timer to pulse a regular small transformer that I think came from a drill charger. So I'm pulsing the low voltage side to make it a step-up transformer and it works very well. At 300 milliamps there is no heat discernible in the transistor and much more light at same amp input compared to the joule thief. I would imagine it may be possible to put a cap on the primary pulsed winding to get it to resonate and gain efficiency. For what its worth.
peace love light
Tyson

[Lidmotor]

Pulsing a small 110v wall transformer backwards

Hi Lidmotor, thanks for reply. I tested the inverted JF circuit with the 555 timer varying the on time of the joule thief and it improved things a bit with some less heating in transistor. However, so far the best setup I have tested is using a 555 timer to pulse a regular small transformer that I think came from a drill charger. So I'm pulsing the low voltage side to make it a step-up transformer and it works very well. At 300 milliamps there is no heat discernible in the transistor and much more light at same amp input compared to the joule thief. I would imagine it may be possible to put a cap on the primary pulsed winding to get it to resonate and gain efficiency. For what its worth.
peace love light
Tyson

Tyson----That idea is something that I have wanted to try for a long time--pulse a wall wart transformer backwards to get enough voltage to light an FL. Now I gotta try it. Thanks for the tip. As much as I love my JT based "Halo Light" your way seems to be a simpler way. There is no BEMF charging I guess but I don't really care if it will works on 300 mA. I suppose you could throw a 1N4007 diode in there somewhere to grab the back spike if you wanted to. On the boat I use a small solar panel to charge up the unit everyday anyway.

Cheers,
Lidmotor

[SkyWatcher]

Hi Lid, yes I've used it for every power outage we've had and it has worked great, though now with the ring-halo floro. it will really be nice. The transformer I've been using that works the best, here is the resistance numbers for transformer.
low voltage winding = approx. 400 milliohms
high voltage winding = approx. 12.6 ohms
I'm using a darlington pair to power it and frequency is around 1.4 khz, adj. with pot of course.
peace love light
Tyson

[SkyWatcher]

pulsed energy capture circuit

Hi folks, just want to share an interesting circuit I've been testing. It captures normally wasted energy similar to whats called a tesla switch. It also lights up the halo bulb equally well as it did without the energy capture. Reason for using the lower voltage 1.2V rechargeable cells in parallel was to make it more efficient, similar to the idea of Peter L's attraction motor, less counter voltage to detract from input. heres a cad pic, hope you find it useful.

[morpher44]

Joule Thief With Honeycomb Bifilar Coil

YouTube - Joule Thief With Honeycomb Bifilar Coil

I've been wanting to try to make a honeycomb coil.
I had read that these have very large inductance for a
small volume, are easy to wind, less wire, less inter-turn
capacitance, and are quite nice to look at.

I thought it would be interesting to see if they could work
with a Joule Thief.
It works!!
I used two 24 AWG wires, one green, one copper, wound
1-to-3-to-5 ... and so on. I had two sets of seven 1/8 in dowel pins.

The honeycomb coil is a coil that Hendershot used in his toy airplane motor circuit, and was used by ham radio gurus back in the day.

They are very nice coils.
This was my first attempt at such a coil. I'm sure others can do better than me.
This sort of coil is another alternative in a "Big Joule Thief" design.

[morpher44]

honeycomb experiments.

What improvement is this going to have over a conventional air core coil?

With a small compact coil, especially with a ferrite core, the length of wire needed for a certain inductance is less, and the resistance is lower. It takes dozens of feet of wire to make a 100uH coil on an air core, even more for a honeycomb coil, and the resistance might be more than a dozen ohms. I can wind a 100 uH coil with a foot of wire on a ferrite core, with a DC resistance of less than a tenth of an ohm.

The special coils such as honeycomb coils are great for high impedance circuits such as receivers, but for low impedance, the ferrite core coil has the lowest resistance.

Oh, BTW, instead of honeycomb, it would be easier to wind a spider web coil, where the coil form is a flat piece of wood or fiberboard with notches cut around the outside edge.

For Joule Thief, it think it is worth experimenting with "air coils" such
as honeycomb and spider web, and also just plain Tesla-style bifilar flat spiral coils.

The spiderweb and honeycomb have that wire-crossing
caduceus coil thing going on, which might have unknown
anomalies -- scalar waves???

Ferro material & Iron suffers from hysteresis, which can eat power unless you have a very nice material with a good B-H curve.
Air responds quicker -- and is "free" (for now anyway).
Wire is abundant from old junky equipment.

The Joule Thief is ALMOST self running and the battery can
possibly be removed and replaced by power pulled from
the VLF and AM radio spectrum ... and air coils are the
way to go for that ... with high Q.

I think it would be most impressive to make a Joule Thief that
runs on NO batteries.

[ashtweth]

Guys still going strong here and providing fan power and light and conditioning batteries .

i dont think you need 2 toroids but here they are as we are using them ATM. This is just the Schemo out of the video.
Imageshack - panaceajoulethiefschema

Ash

[dllabarre]

Hi Lidmotor, thanks for reply. I tested the inverted JF circuit with the 555 timer varying the on time of the joule thief and it improved things a bit with some less heating in transistor. However, so far the best setup I have tested is using a 555 timer to pulse a regular small transformer that I think came from a drill charger. So I'm pulsing the low voltage side to make it a step-up transformer and it works very well. At 300 milliamps there is no heat discernible in the transistor and much more light at same amp input compared to the joule thief. I would imagine it may be possible to put a cap on the primary pulsed winding to get it to resonate and gain efficiency. For what its worth.
peace love light
Tyson

Can you post a schematic with component values, toroid wire sizes and number of turns so I can reproduce?

Thanks,

[Watson]

Guys still going strong here and providing fan power and light and conditioning batteries .

i dont think you need 2 toroids but here they are as we are using them ATM. This is just the Schemo out of the video.
Imageshack - panaceajoulethiefschema

Ash

I noticed that below the 555, the 4.7uF capacitor, pins 2 and 6 and resistor are mistakenly connected to ground. I'll keep my eye out for further errors.

BTW, my browser is having to block popups from that obnoxious Imageshack. Popups are nothing but a nuisance. Try FOTKI - it's free.

[Watson]

For Joule Thief, it think it is worth experimenting with "air coils" such
as honeycomb and spider web, and also just plain Tesla-style bifilar flat spiral coils.

The spiderweb and honeycomb have that wire-crossing
caduceus coil thing going on, which might have unknown
anomalies -- scalar waves???

Ferro material & Iron suffers from hysteresis, which can eat power unless you have a very nice material with a good B-H curve.
Air responds quicker -- and is "free" (for now anyway).
Wire is abundant from old junky equipment.

The Joule Thief is ALMOST self running and the battery can
possibly be removed and replaced by power pulled from
the VLF and AM radio spectrum ... and air coils are the
way to go for that ... with high Q.

I think it would be most impressive to make a Joule Thief that
runs on NO batteries.

Best of success on the no batteries. I've built several JTs with no batteries. Problem is that it requires a bit of elbow grease from the user to make it light.

I've built more than a dozen JTs with air core coils, lately the one I used to 'wirelessly' power the LED.

I see some differences between a toroid and an air core JT:

* The permeability of the air core is one (unity).

* For a given amount of inductance, the number of turns of the air core has to be greater.

* The greater number of turns means the wire is longer.

* The longer wire means the coil has greater resistance, and hence greater "I squared R" losses.

* If I try to lower the losses, I have to use heavier wire.

* Heavier wire means the coil is much bigger. And even with heavier wire, the Q of the coil is still lower because of the higher resistance compared to a toroid.

I've never experimented with honeycomb coils. But they are still air core, and it looks to me as if the wire is longer than it would be for a straight air core coil. So I would think that the resistance would be greater. One thing is certain: there is no problem with core losses.

[morpher44]

honeycomb

I've never experimented with honeycomb coils. But they are still air core, and it looks to me as if the wire is longer than it would be for a straight air core coil. So I would think that the resistance would be greater. One thing is certain: there is no problem with core losses.

No I don't think the wire is longer with honeycomb.
I was able to get a 250uH coil with only about 20 turns or so.
It was quick, easy, and they look nice.
The resistance was less than 2 ohms.

[Watson]

No I don't think the wire is longer with honeycomb.
I was able to get a 250uH coil with only about 20 turns or so.
It was quick, easy, and they look nice.
The resistance was less than 2 ohms.

The resistance is the problem, too much I squared R losses. Two ohms begins to drop an excessive amount of voltage at currents more than a few hundred mA. A toroid with 6 to 10 turns of 24 AWG wire might have an inductance of 100 to 300 uH and a DC resistance of much less than a hundred milliohms.

Also, the amount of stored energy is equal to one half of the inductance L times the current I squared (skip down to stored energy here). So it's better to reduce the inductance and increase the current, since it goes up as the square of the current. (Also see the Q factor section at the above link.) Stored energy is what you want, because every time it oscillates, the JT transfers the inductor's stored energy from a lower voltage to a higher voltage.

[Watson]

Guys still going strong here and providing fan power and light and conditioning batteries .

i dont think you need 2 toroids but here they are as we are using them ATM. This is just the Schemo out of the video.
Imageshack - panaceajoulethiefschema

Ash

I also noticed that there is no bypass capacitor across the 555. A bypass capacitor is really important here. See the 555 datasheet for details.

I saw that the power input was 12V unregulated. This is then fed into a 7812 12 volt regulator chip. It's important that the input to the regulator must be at least 2 to 3 volts greater than the output. If it drops below that, then the regulator will no longer regulate.