Joule Thief

[timmy1729]

@Timmy1729

This link gives some good instructions on how to build a Joule thief.

http://www.google.com/url?q=http://www.evilmadscientist.com/article.php/joulethief&sa=X&oi=revisions_result&resnum=2&ct=result&cd=1&usg=AFQjCNGhx6mr7i8F3HwhKPqShhd6aXzTJw


 

@Xee2
Thanks for the link!
I've already built two JT's that work wonderfully. I was just asking if one of those transformers I have can be used to make a  - JT. Or were you replying to an earlier post of mine?

[Mk1]

@Timmy1729

You take the time to remove the transformer from the pcboard and then check all the connection with the multimeter and write down your findings, usually set the meter on 200 ohms if you don't see anything it means there is no connections between them, find all the ones that show reading on the multimeter note the the location and resistance on paper this will be the map of your transformer.
But usually 2 connector on bottom of transformer indicates 1 coil,4 = 2 coil , 6 =3coils, etc.Only then you will know if the transformer will fit the built.Pretty much any type of transformer (ferrite or not)will work if it dose not its not connected properly.Also if you get the led to light in the regular jt way it means it is well connected but the real power comes from the last coil the highest ohm rated and still not connected to anything if you connect the multimeter to it you will only get ac voltage It is the reason you need to rectify it with a diode bridge then you will have dc.

[xee2]

@Timmy1729

Finding a cheap transformer that will work well is not easy. That is why we are interested in the Fuji transformer. Since you have made a Joule thief before, you should be able to make one using the two lowest resistance coils on a 3 coil transformer like Mk1 did. The Joule thief does not have to have a bifilar transformer. Then hopefully you will get some higher AC voltage out of the other coil on the transformer. But it probably will not be as high a voltage as with the Fuji transformer unless you use a higher battery voltage.

[Mk1]

@Timmy1729

You don't need to take the actual transformer apart, but you need to remove it from the pc board it is soldered on .
the part aren't hard to find or costly,Pick them from any electronic equipment,old radio,stereo old pc any thing you can get your and on , do not buy anything nothing is gained from that.The power you will get out of it will vary widely depending on the transformer.IF the power is enough for fluorescent tube most likely not, but you still get a lots more useful voltage then 1.5 volts i did get a neon working at about 80 to 100 volts dc.
Fluorescent need more voltage then that.But those high voltage are not very useful except if step down or used on fluorescent or led application.
The fuji circuit is really good,but i don't really trust it for elongated period of time since its not built for constant work or longevity ,  Its built to be put in the trash and used for minimal period of time.

I find the most interesting parts out of recycling my self , parts i would not be using otherwise and learn about other parts.

The fuji showed us the potential of transformers now we need to look for ways of getting more current since voltage is not a problem .

[HeairBear]

Why work on the current? Isn't the idea not to use current? Wouldn't it make more sense to design devices that use much less current? Current is what you are paying for and wasting as heat.