Joule Thief

[xee2]

@ jeanna

Changing one thing at a time is always best. But I think I have found the key to getting good performance. It seems to be the turns on the toroid. I do not know what the best turns numbers are, but it seems that toroids with similar turns have more similar performance than those that have different turns numbers.

For R=10K and base cap = 1000 pF

case 1:    2"x0.75" toroid  >>         collector coil = 40 turns & base coil = 10 turns >>> 3 mA and 54 volts (original test coil)

case 2:    1"x1" toroid       >>         collector coil = 36 turns & base coil = 9 turns   >>> 3.5 mA and 51 volts

case 3:    1"x1" toroid       >>         collector coil = 20 turns & base coil = 20 turns >>> 11 mA and 30 volts


NOTE - case 1 and 2 have very different toroids but about the same turns and they have about equal performance

NOTE - case 2 and 3 have identical toroids but different turns and they have very different performance

[Mk1]

@ist

The pictures are dark i can't see much. Sorry. But the good news is there is only 2 way to go.

@jeanna

The difference is one has a core that saturate and other doesn't . 

[Pirate88179]

@ All:

I was reading in one of my electronics books again....yes, I know.....and at the end of the book, they spoke of a wound ferrite toroid for use in a power supply.  They said it was like a choke but, under high power and high volts, to keep the ferrite from getting saturated, they cut a slot in the toroid.  They said this slot could be only a few thousands of an inch wide, but it broke the circle and therefore the core could never reach the saturation point.

Now, I no longer have any of my diamond machine tools, but, I can probably rig a way with a few things I have to cut a slot in one of my toroids. (iron oxide is about 8.5 on the Mohs scale of relative hardness, diamond being 10, glass being 5.5)  Does anyone think this might be a way to go here?  If the core was never able to saturate, then we could feed it whatever we wanted and have no problems.

But, since we are only using an AA battery, maybe this would be a high performance mod that we do not need?  I will have to study this in more detail but, I am just tossing this out there.  Maybe this would allow the use of a heavier transistor like some here have been using without the additional amp (mA ) draw?  I am really impressed by the work being done here and the information that is being exchanged.  Once again, I am very proud just to be associated with you folks.  Keep it up.

Bill

[xee2]

@ jeanna

Boo. This is a bad idea. You should sick to what you were doing. I get high voltage but almost no current. I can not even light up one of my good LEDs. Bad idea. But nothing tried nothing learned. I am sorry for wasting your time.


It looks like something is damaged. Before LED lit brightly with 50K resistor and now it won't even light up. I am not sure what is wrong.


EDIT:  Yeh. Problem was the LED was damaged. New LED lights brightly with 10K resistor.

[innovation_station]

awsome bill...

reminds me of this video i saw ...

from mit teck tv

http://ca.youtube.com/watch?v=Pl7KyVIJ1iE&feature=related

i have a few flyback cores round...

also some feroite transformer cores ..   might tackel em after thease 4 mag amps are built and working properly.

ist