Big Joule Theif

[jeanna]

Hi folks, thanks for replies to my posts. jeanna the toroid i have is an iron powder one from a computer psu, so results aren't very good, but it has a total of 36 turns for bifilar meaning 18 for primary and 18 for feedback and pickup(secondary) has 80 turns using 24 gauge for all coils. I haven't checked to see how many turns light a single led but it does as is and i am using a dmm. I wonder if any other material can replicate what ferrite can do thats readily available and cheap aside from figuring out an aircore design that performs as well. I had an idea for an aircore setup that starts with pickup windings on a cardboard tube or whatever then over that the primary bifilar then over that more pickup windings, this way we can capture all the flux, i think. Though using a ferro type core may gate extra energy that pure copper coils may not be able to.
peace love light
Tyson

Hi Tyson,
OK good.
The jt you made with this unknown toroid is turning on the transistor. (the light is on)
That is the first thing to check.
The dmm, as I said, is not capable of measuring the volts.
To get the accurate measurement, you must remove the led from the C-E, and use a scope.
If you do not have a scope, here is what you must do to determine the volts:
(I hated doing this enough to make me spend $189 for a hand held scope.)

Put the 2 secondary leads into the ~ sides of a full wave bridge rectifier (fwbr) now, you must extend this and add 2 more diodes to help the fwbr do its job, so put one more on the + and - ends of the bridge keeping the polarity the same.
Get one of those high voltage caps from a camera or another can type cap you have that has high voltage, and put it into the ends of the diodes of the extended fwbr, again observing the polarity.
Give it maybe 20-30 seconds and then using your dmm on HVdc measure the voltage you collected.
I am sure you will be surprised.

OK?

yes, you can do this with air core but you need 600-1000 turns to get the same thing as 60.
the ferrite is amazing and even a powered one works fine as I saw when I used the tiny orange one.
What does not work fine is a choke. (You do not usually know what you have.)
Most of the ferrite toroids are less than 50 cents. I call that cheap enough.

Availability is less good, but that is because they are used to remove the spikes from circuits, so they are in OEM products and not so available on the consumer level. That was the reason for the tiny orange experiment. (10w GE "energy smart")
Bye the way, that light is great.
It is bright and the battery lasts a long while as it should.

-----
@All,
I was watching a video today and realized that at 9v a 10mA draw is a very different amount of draw than at 1.2v so, do not confuse them.
For instance at 9 volts battery a 10 mA draw is 90mW
the same 90mW looks like 75mA when using a 1.2v battery.

Apples and apples

jeanna

[SkyWatcher]

Hi folks, thanks for replies to my posts. jeanna the toroid i have is an iron powder one from a computer psu, so results aren't very good, but it has a total of 36 turns for bifilar meaning 18 for primary and 18 for feedback and pickup(secondary) has 80 turns using 24 gauge for all coils. I haven't checked to see how many turns light a single led but it does as is and i am using a dmm. I wonder if any other material can replicate what ferrite can do thats readily available and cheap aside from figuring out an aircore design that performs as well. I had an idea for an aircore setup that starts with pickup windings on a cardboard tube or whatever then over that the primary bifilar then over that more pickup windings, this way we can capture all the flux, i think. Though using a ferro type core may gate extra energy that pure copper coils may not be able to.
peace love light
Tyson

[jeanna]

cores or no cores

@Hi area:
There are lots of folks making a special very interesting core over a paper tube (duct tape tube) and getting interesting results.
I have no experience with this but one of them (MK1) found that while the meter pronounced zero for output, he was able to light a white led and an unconnected red led , so, it looks like a great direction to me.

@Skywatcher,
So Tyson,
How many turns of primary are making the basic jt turn on the led in the C-E spot?
That is the first question I want to ask.
The lower the permeability the higher the flux and the more turns are needed to make the toroid oscillate.

btw, the cfl I used was a GE energysmart one. This is the new cheap kind that gets hot.

jeanna

edit
Skywatcher,
I missed a couple of posts and I want to ask you if you are using a dmm for your voltage results?

A dmm simply cannot see the volts. In fact if this is 8v shown from a dmm, watch out!! You probably have 80-150v
You will see the leds shine very bright for one moment then go out.
We were all puzzled about this when we first were doing this because nobody had a scope.

If these volts are coming from a scope, what is the frequency?

[area46241]

electro/magnetic...

Hey there skywatcher I would like to say that the core needs to be magnetic if you want to tranfer the primary energy into magnetic flux then the flux tranfers back into the secondary coil all at the same time. Now I have been wondering if a coil of any efficiency could be constructed by creating an open air coil with another coil wraped around the first all taped or paper wrapped. Has anyone here ever wound such a coil?

[kooler]

toroids

hello
the pc power supply has mostly powder iron the big ones are like mag amps
but if you get a psu with toroids that have white plastic covers on them and are bifiliar wound.. those are real good ferrite toroids..+ you can use the soft copper wire that is on them or you can strip the plastic off to get a better windings on it..
psu's are still a great source to get transistors , scr's, mosfets , schottky diodes
and heatsinks.., there is always a good size bridge rectifier in it too..

and if you don't mind desoldering go for it..
most pc shops will give you a box full of them.. free
the newer the psu the more ferrite in them..
hope this helps

robbie

[Bob Smith]

Hi folks, ok the aircore isnt working so great at 1.2volt input, so im looking at the guts taken from a few cfl's, problem is there were no toroids in them, just little transformers that look like they may be ferrite, the metal is black in color. if they are ferrite has anyone tried those, not sure how id wire a bifilar on there though, any help appreciated.

Tyson, you can also salvage toroids from burnt out computer power supplies. They're often thrown out when the caps inside blow, but there are a bunch of toroids, resistors, etc. If you know anyone at a college or school board IT department, or someone who owns a computer shop, faulty power supplies are continually thrown out there - a good place to ask.

I don't know if these toroids are useable (solid or powdered ferrite?) - perhaps someone else can verify.
Bob

[SkyWatcher]

Hi folks, ok the aircore isnt working so great at 1.2volt input, so im looking at the guts taken from a few cfl's, problem is there were no toroids in them, just little transformers that look like they may be ferrite, the metal is black in color. if they are ferrite has anyone tried those, not sure how id wire a bifilar on there though, any help appreciated.
peace love light
Tyson

[SkyWatcher]

Hi folks, well i dont think my toroid is ferrite jeanna and probably why it stinks at outputting decent voltage, so i am experimenting with air core jt's. The first one is working well with a brooks coil geometry, plastic spool taken from the wire the shack sells. first test coil can light a flouro at minimum 6 volts, though not great because i wound to much for the primary. Primary is 26 gauge @ 6 ohms and pickup coil is 30 gauge at 42 ohms, so i will rewind another plastic spool with less primary turns for lower input voltage and the same or more on the pickup coil. Anyone else tested any aircore jt's using a pickup(secondary).
peace love light
Tyson

[Tectalabyss]

JT Help

Hi Tyson,
I wrote this as an answer to a similar question.
Let's see how it does.
Please ask the questions that this doesn't cover after you get this.
thx,
j
===:

The gauge I use for the primary bifilar is 24awg. I got this from a telephone extension cord.
The length you will need to make this first one will be about 14 inches of each wire.
This depends on the fatness and diameter of your toroid, so this is just a guess. (I use a small one and it takes 11 inches of each wire and is very generous.)

After you have made a plain joule thief make a second one exactly the same way. Put the led into the led spot but do not solder it.
Remove the led when you prove that the circuit works.
Now, wind a secondary.
The choice of gauge for the secondary is up to you.
The thinner wire will make higher voltage, but the problem with really thin wire (like 30awg from radio shack) is the insulation is easily scratched. If it gets scratched you will have little to no voltage from your output.
One more thing about the secondary.
The side of the primary that connects to the collector coil is the part that is being "transformed" so, if you have 10 turns on the collector side (you do now if you are following the makezine video) Then double that will be 20. So, make your first secondary with 20 turns.
This will give you a starting point for reference voltages.

Now, you have 2 very useful circuits.
1-the plain jt is the best way to get the last bit of joules out of the battery. It makes a terrific emergency light.
2- The battery needs to be a little higher for the secondary to work. There are exceptions to this, but most of the ones that use a secondary run down after the battery is at about 1.1v.
So, you use the jt with secondary then when it is no longer bright you switch that battery to the plain jt.
This does not apply to a rechargeable battery.
Do not use a rechargeable in a plain jt, because it is not good for batteries to be so thoroughly drained.
(I could never figure out why but it seems to be so.)

After you have made these 2 you can start experimenting.

I have found that it is very important to make the wires wound snugly onto the toroid.
It is possible to have a good one that is loosely wound but if you want high voltage... get it tight around and try to have as many winds as you can actually in contact with the ferrite.

(I believe there is a difference in opinion about loosely wound together, but this is not about wound together, this is about being tightly wound on the toroid itself.)

That toroid is a powerful source of "something" that makes high volts.

I hope this helps.

jeanna
===========
a couple more points:
The job of tuning the primary is trial and error.

use a pot at the base of the resistor until you know what resistance you want.

I usually wind a few turns for one secondary led and add one turn at a time until the led is too bright, then subtract one. Now that is the number of turns per led. If you happen to own a scope you will also know how many volts.

OK for now,
please ask the rest of the q's as needed.

jeanna

Wow That was a very helpfull Post Jeanna My Thank's to you and all the great people here. Tec

[SkyWatcher]

Hi folks, Hi jeanna. I redid my wiring to see if that was an issue since i was using a proto-board and instead i used a plastic wire strip and that did help, i can now see 9-10 volts ac from meter off secondary with 1.2v input. Though something is still not right since i should be getting much more voltage based on yours and lidmotors setups that seem to use flyback effects from primary collapse. I wonder if the transistor im using is not shutting off sharply and quickly enough, its an NTE392. rather overkill im sure. let me know what you think. Thanks.
peace love light
Tyson

[SkyWatcher]

Hi jeanna, thanks for that info. I removed the 18 gauge, then rewound with 24 gauge bifilar primary which runs the transistor smoother probably due to impedance. Then i put 80 turns of 24 gauge for secondary, though i may have damaged the wire as you've pointed out because i cant get a good reading from a meter around 5 volts ac which does correspond to transformer step-up rules although charging a cap the voltage climbs past 40 volts. From what i know of this, this should act like an ignition coil where the secondary is charged first with first pulse then secondary collapses and gives much higher voltage. If we look at Lidmotors replication of your 3 1/4" dia. toroid, with 300 turn secondary of 300 gauge and a 13 turn primary, that is a 23 to 1 turn ratio and so at 1.5 volts should only be 34.5 volts. So then it does seem that as long as the windings aren't damaged and the transistor is firing how it should then flyback is at play here as you may already know. Similar to pulsing a regular transformers primary with dc pulses and getting high voltage off secondary via flyback effects. Anyway just trying to figure out why the differences im seeing.
peace love light
Tyson

[jeanna]

Hi folks, Hi Jeanna. I'm about to do some more testing with the toroid i picked from a computer psu, green in color at 2" dia. X 1 1/4" inner dia. X 3/4" height.
What sort of primary to secondary ratios and wire guages are you using for some of your various lights, like the one with loa inside the table lamp with shade or the small toroid light you salvaged from the cfl. I'm kind of a light nut myself, leds and all. I like the fact that when the rare occurrence of a power outage (rare thankfully) i always have enough light source with cfl's, halo ring bulbs (best), and led's which seem to be edging out flouro's since there cleaner for environment and more reliable usually, though the color harshness could be helped by diffusers as you've shown.
My toroid now has about 50 turn bifilar 18 gauge, and was thinking some 24 gauge for a secondary, though i also have 30 gauge. Maybe the 30 gauge would better for a flouro and 24 for led's. What kind of ratios would you use for this toroid at 1.2v of course, your ideas are very much appreciated. Thanks.
peace love light
Tyson

Hi Tyson,
I wrote this as an answer to a similar question.
Let's see how it does.
Please ask the questions that this doesn't cover after you get this.
thx,
j
===:

The gauge I use for the primary bifilar is 24awg. I got this from a telephone extension cord.
The length you will need to make this first one will be about 14 inches of each wire.
This depends on the fatness and diameter of your toroid, so this is just a guess. (I use a small one and it takes 11 inches of each wire and is very generous.)

After you have made a plain joule thief make a second one exactly the same way. Put the led into the led spot but do not solder it.
Remove the led when you prove that the circuit works.
Now, wind a secondary.
The choice of gauge for the secondary is up to you.
The thinner wire will make higher voltage, but the problem with really thin wire (like 30awg from radio shack) is the insulation is easily scratched. If it gets scratched you will have little to no voltage from your output.
One more thing about the secondary.
The side of the primary that connects to the collector coil is the part that is being "transformed" so, if you have 10 turns on the collector side (you do now if you are following the makezine video) Then double that will be 20. So, make your first secondary with 20 turns.
This will give you a starting point for reference voltages.

Now, you have 2 very useful circuits.
1-the plain jt is the best way to get the last bit of joules out of the battery. It makes a terrific emergency light.
2- The battery needs to be a little higher for the secondary to work. There are exceptions to this, but most of the ones that use a secondary run down after the battery is at about 1.1v.
So, you use the jt with secondary then when it is no longer bright you switch that battery to the plain jt.
This does not apply to a rechargeable battery.
Do not use a rechargeable in a plain jt, because it is not good for batteries to be so thoroughly drained.
(I could never figure out why but it seems to be so.)

After you have made these 2 you can start experimenting.

I have found that it is very important to make the wires wound snugly onto the toroid.
It is possible to have a good one that is loosely wound but if you want high voltage... get it tight around and try to have as many winds as you can actually in contact with the ferrite.

(I believe there is a difference in opinion about loosely wound together, but this is not about wound together, this is about being tightly wound on the toroid itself.)

That toroid is a powerful source of "something" that makes high volts.

I hope this helps.

jeanna
===========
a couple more points:
The job of tuning the primary is trial and error.

use a pot at the base of the resistor until you know what resistance you want.

I usually wind a few turns for one secondary led and add one turn at a time until the led is too bright, then subtract one. Now that is the number of turns per led. If you happen to own a scope you will also know how many volts.

OK for now,
please ask the rest of the q's as needed.

jeanna

[SkyWatcher]

Hi folks, Hi Jeanna. I'm about to do some more testing with the toroid i picked from a computer psu, green in color at 2" dia. X 1 1/4" inner dia. X 3/4" height.
What sort of primary to secondary ratios and wire guages are you using for some of your various lights, like the one with loa inside the table lamp with shade or the small toroid light you salvaged from the cfl. I'm kind of a light nut myself, leds and all. I like the fact that when the rare occurrence of a power outage (rare thankfully) i always have enough light source with cfl's, halo ring bulbs (best), and led's which seem to be edging out flouro's since there cleaner for environment and more reliable usually, though the color harshness could be helped by diffusers as you've shown.
My toroid now has about 50 turn bifilar 18 gauge, and was thinking some 24 gauge for a secondary, though i also have 30 gauge. Maybe the 30 gauge would better for a flouro and 24 for led's. What kind of ratios would you use for this toroid at 1.2v of course, your ideas are very much appreciated. Thanks.
peace love light
Tyson

[jeanna]

solar panel

Thanks,

Yes, they could. I have used little solar panels for AAA to D which work quite well.
The sweet thing about the jtc is that even if the sun is not bright enough for a full charge, it is possible to use that battery in the evening for a few hours of light. Good point.
Thanks for bringing it up

jeanna

[Tectalabyss]

tiny orange toroid light

This time I checked to make sure, and it is what I wanted to present.

The reason for this video is because I can see that the toroid is the most limiting factor for making a joule thief. I only realized this when the stock rooms of allelectronics and mouser emptied of the toroids we mentioned in a day.

So, I took the circuit from the 10w cfl that I had removed, and the screw base too.
I could have used the transistor and resistor from the circuit too, but I didn't think about that until later. It was the toroid I was concerned about.

---
yes a solar panel does this, but in the day this light is not needed, so a storage battery of some kind is necessary.
There are videos out there using batteries of aluminum foil and copper, or carbon. I lit a led with 2 of these in series. I didn't try the jtc with that but it would surely work with only 1 instead of 2 in series to some degree.
So, the focus is really on making a bright light with that toroid from the cfl.

And, please keep pushing this envelope, everybody! And, please show others what you have made.

jeanna

edit
let me add the LoA I get from wall mart. I am sure they are in other places. (My hardware store carries some but not all of LoA bulbs.)
They are made to resemble a standard light bulb and have 20 leds in series and a whole lot of protective caps and diodes and resistors and even a fuse, so while I have made and shown(on youtube) how I made a modified LoA bulb into a battery joule thief lamp, I wanted a simpler design.
this eventually turned into the jtpu = joule thief power unit, which is a stand alone joule thief in a switched plug socket which lights one or 2 unmodified LoA bulbs and is entirely portable.

Hi Jeanna
What I meant about the solar panel Is if they had a rechargeable battery they could recharge them during the day.I watched your vidio Great Tec