monster yet efficient and simple joule thief

Step 2 Winding the transformer(inductor)

Now come to the heart of this thing.u can use a ferrite rod if u wish.But it needs 4X turns to achive the power and the magnetic flux leaks from the two end but toroid is ring shaped so and all the flux is in the center so Less than 1% is wasted.
Some people say it is da most tricky part but it simple as kniting a shirt.u can find small cores in cfl bulbs,big cores in psu on ur pc,u can also buy them like me.in my country it cost 8 tk it mean 0.05cent only .

WINDING:i cant show my winding proces cuz i ve wind it.and it took me about 3 days to do it .i did in my class,my home also in toilet.LOL.there is two types winding.1.wind to wire together like ive done in the picture 2. center tap winding.The first one is easy cuz when ur winding 80 turns u only need to wind it 80 turns but in the second one u have to wind 160 turns.i am giving the urls of windings.
1.http://www.evilmadscientist.com/article.php/joulethief
2.http://www.cappels.org/dproj/Toroid_winding/Toroid_Winding.html

now my core has 100 turns of wire but u cant turn them like on the urls with only hand.here is the trick ,get a thick jumper wire(magic wand) and wind 5 meter of wire on it.then take out 10cm of wire then wind the toroid like u r sewing a cloth.first place the wand under the toroid and then take it out from the center and again take the wand to the bottom of the toroid and take it out from the center.u should stick a tape on the starting point cuz without it the wire will be loose.when u ve done it in anti clockwise and ur winding has come to the starting point get a transperant tape (very thin one).go round the core about two times with the tape.now start winding again with the same wire and continue this task until all the wire is finish.the tape is not necessary.it is only for neat winding.connect the two wire like it has done on the site of evil mad scientist.
dont worry i will upload a video on youtube for winding.

P.S 100 turns wire is for big core.and 20 turns for small core.big core is for more leds.but small core from ccfl is only for two leds

Comments

[azthinks]

Not bad for a 14-year-old! But I can tell just by looking... that is waay too many windings on the toroid to be efficient. Longer wires have higher resistance. Even just 5-10 turns should be OK. And try thicker wire to lower the resistance. Check out http://azthinks.com/JT_resources.html for more joule thief hints.

[uberdum05]

After I wound it as well, the circuit did'nt work!!(Curse you....circuit =))

[shams]

try using 10 tap 10 winding.And which transistor you are using?

[uberdum05]

Im using a TIP31A, reading the datasheet it says it needs something like 350 Ma to turn on, maby its too much?

[shams]

no it's not too much but how much volts it need to turn on?I've also used this circuit with irf3710 mosfet.and check your winding.It must work.And sorry for late reply I was busy playin games.My dad bought a new gpu for me!!

[uberdum05]

It needs 5 volts to turn on, also what GPU make is your new one?

[shams]

Here read this it might help you!! Initially, I tried a BC107 transistor (because it was to hand) but it would only oscillate if I lowered the base resistor to 220 ohms and when I measured the current taken from the battery it was about 90mA - even before the LED was connected. A BC108 oscillated easily as did a H945 removed from a dead switcher - also a good source of coils/ferrites. But I was intrigued with getting the BC107 to run and added a small capacitor (22nF) across the base resistor to 'kick-start' the oscillations. It worked so well - with various transistors and coils that I was further intrigued to see how much I could increase the resistor value - hence the 20k trimpot. (The 22nF also got over the problem of the oscillator failing when I tried to add an ammeter in the battery circuit). I found it would continue to oscillate right up to 20k ohms and this also had the effect of reducing the supply current (osc only) from 90mA to 800microamps - very important if using batteries. The transistor used in this circuit can be any one of a wide variety of transistors. I recommend trying the 2N4401, 2N3904, and 2N2222, listed in no particular order. Dariusz Flaga in Poland, noted that the BC338 is popular in Europe and that its specifications, including voltage and current ranting, and saturation characateristics, suggest that it is a good fit for this application. Mr. Piggs in the U.S.A. (see the Solar Powered Garden Light, above), successfully used the BC547 on several prototypes. You can even use PNP transistors, but if you do, remember to reverse the battery and LED connections. I have received email from a couple of project builders who used very high gain transistors and had trouble with their circuits. Transistors with high DC current gain (hfe) tend to switch slowly and may operate inefficiently or not at all. Stay away from the very high-gain audio transistors in particular. The small capacitor across the base resistor, as shown in the Rusty Nail Night Light can speed up the transistor and make oscillation possible when you have low a inductance inductor, or if the transistors are a little slow. Speedup capacitors beyond .0033 uf (33000 pf) are probably excessive and may actually slow down the circuit by causing the base to be over-driven. If your circuit doesn't work, consider using a faster transistor.

[uberdum05]

would a darlington pair work well?

[shams]

It will work but it got very very high gain we dont want very very high gain we need single transistor high gain one.man why your JT is not working.I've tought about 20 kids to build this circuit on there own.It's a very simple circuit it should work!!!

[uberdum05]

it's a pain in the butt. I'm more used to building logic circuits with HCF4xxxBEY IC's and using computers.I have currently got an ICT job off my ICT manager, its awesome.

[shams]

wow man you are rolling very high!My bro is studying in electrical and communication eng.And I'm 16.I've started electronics in this year and in 2007 I was building a pulse jet engine and it worked!!And 2006 I was fully on thermal components(engines).I think in the fall 2009 i will be in atomic reaction

[shams]

Try bc547b or bc557b transistor.one is pnp other is npn.This transistors are very high on current gain.Use this for first time

[shams]

5 volts? oh you cant start that thing with that 10 turn transformer.you need atleast 40 turns to kick start that transistor with 1.5 volt.try using low power high gain transistors first.if that works then start with this big transistors.And your core must be ferrite!not soft iron core.My gpu is diamond hd4870 1GB cpu e8500 core 2 duo chipset DX48BT2

[uberdum05]

I got the stripped end of the wire stuck in my finger... OUCH

[shams]

Be carefull man