Joule Thief

[dasimpson]

thanks when i get set on things o do tend to go full bor at it like these to little fellows see pics below one is a ferite bar from a radio 20 turns bifailer the other i got of a well can not remeber what i got it off it was just an experement but was happy as larry when it worked first time the toriod one was allready wound as i say it was an experement and it worked they are 6 winds collector and 5 winds base they both draw about 50ma my battery never run flat i have a solar panel outside my windows that keeps 1 aaa and 1 aa chargeing and trickle charge and i run off them the aa is 2500mah

extra inductor in series do you mean another toroid say tenty turns dump coil (meaning the coil that comes from the secondory of the firct toriod) and the turns needed to get the lgiht needed on the pickup

Hi dasimpson,
Gary is correct about the series and parallel.
It really makes little difference.

I have 2 lamps made in this simple way we are discussing. One has 24 leds with 6 in series but 4 strings of them, and the other has 42 leds with 6 in series again, but 7 strings of them. They are both bright and both last a long time with one NiMH AA that has 2500mAH. If you are using a 600mAH battery, you are doing really well if you get more than 8 hours, especially with that transistor.

Also,
You do not want to kill your rechargeables by taking the voltage too low over and over.

I also want to mention that my best A for one of my toroids is 2Turns on the base and 9 Turns on the collector.
another is 5T on the base, and 8T on the collector.
If you are using the 5/$1 kind from goldmine, I think the best tuning is 6T,6T even, but I am not exactly sure there.
The point is there is a wide range and do not be afraid to get really off balanced.

When you have 2 secondaries, one often goes out, so maybe concentrate on using just one secondary. You can get the 2 to both light the leds but you need an extra inductor in series... more fiddling!

It is great to see you doing this so well and so quickly.

jeanna

[resonanceman]

i use 10 bifilar for the primiery and about 5 turns for every led secondry but i find each time i do that the other led get a little dimmer i am at moment out of enamel wire going to strip a hobby motor in a bit i wont to light 22 leds so by what i have read that sound be a 110 turn secondry but what i dont know what to do is if the 110 choke the oscerlation how to cure that and keep all led at full brightness

the parts i use are 1k resister bc337 transister untill i can get some 2n3904's a 1 inch black toroid and cat 5 wire

dasimpson

did you try your JT with less than 10 tirns bifilar?\
If  it will not  run  with less than 10 turns it is probably  an iron powder  toroid.......or a choke.
If that is the case........ your top priority  could   be to find a better toroid.
As I  understand it.... iron core  troroids  are used alot in  power supplys....... An easy but probably not completely  accurate explination is   some  toroids  are just not fast enough for JTs.
Almost any toroid  intended for high  frequency use will probably  work well.
The 5 for $1 toroids from Electronic  Goldmine  are a  good  inexpensive  toroid to start  with.


gary

edit

with  a good toroid  you should  be able to run  with  3 or 4 wraps bifilar......  right now  your  secondarys  are working kind of like  step down  transformers..... with 3 wraps   your same secondarys would work like step up  transformers. .

[dasimpson]

ok these are what i have see pic below the black one is 2.5cm the yellow one is also 2.5cm the green and blue one is 1.5 cm from a blown cfl the little green one i cont remember were i got it that is 1cm what one would you say is best

dasimpson

did you try your JT with less than 10 tirns bifilar?\
If  it will not  run  with less than 10 turns it is probably  an iron powder  toroid.......or a choke.
If that is the case........ your top priority  could   be to find a better toroid.
As I  understand it.... iron core  troroids  are used A in  power supplys....... An easy but probably not completely  accurate explination is   some  toroids  are just not fast enough for JTs.
Almost any toroid  intended for high  frequency use will probably  work well.
The 5 for $1 toroids from Electronic  Goldmine  are a  good  inexpensive  toroid to start  with.


gary

edit

with  a good toroid  you should  be able to run  with  3 or 4 wraps bifilar......  right now  your  secondarys  are working kind of like  step down  transformers..... with 3 wraps   your same secondarys would work like step up  transformers. .

[dasimpson]

you lost me with this part  "with  a good toroid  you should  be able to run  with  3 or 4 wraps bifilar......  right now  your  secondarys  are working kind of like  step down  transformers..... with 3 wraps   your same secondarys would work like step up  transformers. .

and as far as i know ant psu ones good cos they have to work in the 60mhz range

[resonanceman]

ok these are what i have see pic below the black one is 2.5cm the yellow one is also 2.5cm the green and blue one is 1.5 cm from a blown cfl the little green one i cont remember were i got it that is 1cm what one would you say is best

It is impossible  to tell  how well a toroid  will work by looking at them........but many iron powder toroids are painted.......most ferrite toroids  I have seen are  uncoated.


It  would  be very helpful  if you  would  say if you  have tried  using less than 10 wraps  on your  JT


Is  it possible for you to find  an old TV or monitor  tear apart?
The  flyback  transformer in these  has a great core for toroids.......it  can  also  often be used   as is.........if you can't get  the  shell off of it.
They  are not easy to  get out....... but worth the trouble.
Be very careful if  you have not messed with  old TVs before........the  sides of the picture tube act as  a big capastor........it can sometimes hold  a lethal charge for months ........ so make  sure  it is discharged before  you try taking any parts  off.

gary