Joule Thief

[jadaro2600]

HELP!!!!

I have no idea whats happened with my latest joule thief.  I was using an old toroidal transformer - very large, lots of turns...still dont know how many, in a typical joule thief circuit except i had 2 transistors coupled like a darlington pair (i think ).  They're 2n3904's and i used an old AAA battery. The transformer has a secondary winding which i had wired up to a bridge and 10-15 LEDs.  FirstIy i tried about 50 leds in parrallel with the emitter collector of the second transistor in the pair, and they all flashed very brightly as well as the 10 LEDs on the secondary, which flashed dimmer but faster. I then put a 6 volt motor in place of the 50 LEDs.  To my utter surprise the motor worked, as well as the extra LEDs on the secondary.  I was sooooo happy, I cackled like Dr Frankenstein....This was the most power i'd got with such a battery.  I left it running for about 40 mins, and then put it away till the morning.

Anyway, tried it again this morning, and now i cant get a single LED to light with the circuit, unless i use a big 4.5 volt battery.  Whats happened?  Ive tried changing the transistors, but to no avail.  I've tried the original evil madscientist circuit with no secondary connection....and still nothing.  Its almost like my coil has stopped working....why would this be??  I am just making a silly mistake??


Thanks in advance for any wisdom or help offered.  I'll be getting a video camera for my birthday, and if i can get my JT back in order i'll definitely be making a video.  Thanks to all of you for the continual inspiration 

Not sure how your running wire to your motor, but the motor itself might have been fubar'ed by the high voltage spikes or there may have been current feedback into the jt circuit: protect the motor with a capacitor and diode protect the the jt from the motor, like so

JTC----|<|--(-)--{ | }    jtc > dioides > (capacitor) > motor
JTC----|>|--(-)--{ | }

NO good at ascii art, sorry, and my idea may not be that great after all.

[RAF]

Here is one i haven’t read yet.

But first the setup, after i modified the fugi camera i found an old amp with two seemingly
matched white plastic coated toroid. Took the wire off both and wound them on one so no i do
not know how many turns but it is full.
Used a 2n3904 transistor , 1k ½ watt resister and 1.2 v. 700 mah. AA NiCad . Lit out LEDs like
crazy.
To see what out put voltage it was giving, i manufactured a full wave bridge rectifier out of 4
1n4002 diode . Having some capacitors from the fugi i hooked one to the DC side of the rectifier
. A solid 58 V. , i was so impressed i put a 13 Volt brushed DC motor across it.
The motor ran at great speed for a sec then slowed, not to surprising the capacitor held at 4.3
volts but as with the LEDs the amp draw also went down a little.

Sooo... the thing that i find weird , decided to try a 12 volt brush less DC motor.
At first the motor takes off again with great speed then slows , suddenly reverses direction and
runs in that direction maintaining a 4.3 volts at the capacitor until disconnected .

Just wondering if any one had seen this before, and could it be even though i have a capacitor to
smooth out the pulse that it is still pulsing the motor and messing up the timing of the motor.
Like most of us i have a limited amount of tools, Volt meters and AC Amp meters all over the
place but just got a DC Amp meter this week, so no Scope yet. LOL

Thanks to All

[gadgetmall]

@jadaro2600

For the mk2, look a page 284 285 286.

my computer got attacked again, i connected my network on the windows side 2 min and check with spy bot and got 214 infection on my window partition, my windows is not booting anymore, this is really not normal.I have not used it in any way and it did not recognize my network card.I did make friends over here but also enemies.

Mk1

Hey Mark . Sorry your getting Bugs . I used to be a fan of norton until i found Avast 4.8 try it  it had a very good network and web shield and an excellent Virus program that updates and its all free . If you can run that malwarebytes program on your computer instead of spybot .A you can see Spybot sucks and can't find or stop it all . apparently you have got something still hiding itself in the partition .

Al.

[innovation_station]

well guys i need a supply jt unit


real simple ....  so i will make one

i have been playing with a mk2       7x7x5x5 and i wanted to see if infact it is working as planed so i tryed to recharge a dead shake it .... system ..

it did this well and darn fast ...  then i tryed on another feed from the same unit ... i added a 3.6v  350 mah  and sure enough it charged that one quick too

so i will make a unit that will run from a aa power the mk2 unit it will charge 2 3.6v cordless fone batteries ...  then we will take the out put from the to 3.6vdc batteries and we will devide it by 3  for both and feed the 6 pac ...

well time to whip it up


also i mounted the crank and power unit from a crank flash light i will add a mk2 to it too and a battery to be recharged .. then we can give her a few cranks ..and away we go ...


ist!!

[Mk1]

@ist

Good work, there ! I can see you did a simple version of my experiment, lol and did not go overboard , and multiplied everything by 10 as you usually do , ok by six , but you did show restraint .lol

You can also connect all 4 pickup coil per jt in series , or 2 in series then rectify and feed back to the other coil , it charges faster.