Joule Thief 101

[resonanceman]

;D100 spiky volts?
That is nice to know.
I think I will pick up one of those next time I am in wallmart. I need another plaque, so that might be soon.

Jeanna

No..... not spiky volts......normal volts
From my experience  the reading on a meter  with spiky voltage  means  very little
With the meter  connected  across the  LED array I have  lit the array pretty brightly with as much as 250V  and  as low as less than  one volt
How brightly the array lights seems to be dependant more on the power  level that the circuit can deliver more than the voltage.

About this array .......was out of the first Light of America floodlight that I ever bought.
I use it as  my general purpose  load for my circuits.
It is great because it lights a little with almost any application of power.
With very low power  just a few LEDs will glow purple .

The  new flood  lights  do not  react like this.......they require much more power to turn on........when they come on they are nice and bright.

Another thing to think about ........ my first flood lights  were VERY easy to take apart ......but each new generation  has gotten harder to take apart
The last  one I took apart  was a real pain ........I had to CUT the reflector around  the circuit board  then  pull  the board out.
The back  of the array was also coated with some kind of glue.......effectively making it about twice as thick.

Because of these  things  I do not plan on buying more  floodlights  to  take apart to get the arrays .

You might look for the  light in the picture below.
It is a little smaller........  and  cheaper......
If I remember right it has  24 LEDs  but it is almost  as bright  as my 90 LED array because  these seem to be straw hat  LEDs
I have  bought  several  of these.........the electronics  burns out fast .......but the LEDs  are still good.........and  quick and easy to get to.

I might try to get that much from the little one.
I just made a bunch of turns and it seemed good at 50-60v at 470r, but with less resistance or more turns or both 100v is probably possible.
I was addressing the cfl. I do not think that is possible with the tiny toroid.
I made one at the end of the summer from my 3/4 inch toroid that lit a 4 inch 4watt tube, but it fizzled. I think there were so many turns, that they must have shifyed and choked it.

I notice xee2 has re-wound his that got choked and he is getting good HV from it.
I completely agree.


This is something like the russian pictures from the other day.

I also had good results by winding the base coil around one toroid, and the collector coil around both. This gave me 2 toroids with similar voltage output, but if I remember, different shape.

I find it interesting to light a cfl, but it is not necessary nor very bright. Certainly using a bunch of leds is the brightest way.

My goal with the Little torids was for lighting  a LED array .......I finally replaced my  Dewalt 18 V batterys ........ Now I have  an 18 V light to convert to LEDs
I plan  on using some feedback....... the original bulb only lasts around 4 hrs per charge........I am shooting for  a week or 2 with LEDs .......
A  LOA 60 LED flloodlight  array just  barely fits  into the place the  reflector  used to be.


You got me wondering  if it is possible  to light a CFL with the little  toroids  ........  I wonder  of it is possible   to put the toroids both in series and parallel like we do  with LEDs
So far with my candy cane coils the series coils only seem to add power not voltage.

Just maybe....... the base coil  can be " shortened " by not putting it though all the toroids......... that might  change the transformer ratio.

gary

[jeanna]

Thanks gary, I have seen those. I will try one next time.

=====
I want to give a follow up picture of this tiny toroid as a finished lamp. With 42 leds, it is only marginally brighter than the 24led one, similar to itm which is a surprise, and may relate to very low amps per led. I turned the cluster and it got brighter, so I might just need to play with the directions of the leds.
I tried to make the lights face outward in a hemispherical way. You can see I was not successful, and I may be able to improve this light by carefully bending the led wires. I put hot glue on the legs so shorting won't be an issue.
1- the cluster run by the tiny toroid in place and on.
2- a piece of plastic bag (!) wrapped around the cluster to give an even diffusion.
3-all put together and on.

jeanna

[b_rads]

Thanks to ALL for the great info on this wonderful circuit.  I built my first basic Joule Thief this weekend and it worked as advertised.  In reading this thread, I created a guide from the posts here and have made it available in the download section.  It helped me and it might help others.  Thanks again to ALL.
http://www.overunity.com/index.php?action=downloads;sa=view;down=441
Joule Thief 101.pdf

[tikbalang]

i am not getting optimum brightness from the leds.

i built the circuit from the 3rd post of this thread combined with jeanna's instructions on page 5 of this thread.

i tried 4 sets of coils, with CFL toroids:

A. 3T+3T/8T (default CFL winding)
B. 5T+5T/5T (cat5 wires)
C. 9T+12T/10T (jeanna's, #24 magnet wire)
D. 8T+8T (no secondary, cat5 wires)

my output is 1 led at the collector or 5 leds in series at the secondary coil. the leds light up but not as bright as when driven with 20ma constant current source.

the first 3 did not differ much in terms of brightness, both for 1led and 5led config. the last one seemed just a tad brighter but i could not fit anymore windings.

is it ok to jumble up the wires? can we establish a ratio to the windings? is it ok to use thinner wires to fit in more windings?

[resonanceman]

i am not getting optimum brightness from the leds.

i built the circuit from the 3rd post of this thread combined with jeanna's instructions on page 5 of this thread.

i tried 4 sets of coils, with CFL toroids:

A. 3T+3T/8T (default CFL winding)
B. 5T+5T/5T (cat5 wires)
C. 9T+12T/10T (jeanna's, #24 magnet wire)
D. 8T+8T (no secondary, cat5 wires)

my output is 1 led at the collector or 5 leds in series at the secondary coil. the leds light up but not as bright as when driven with 20ma constant current source.

the first 3 did not differ much in terms of brightness, both for 1led and 5led config. the last one seemed just a tad brighter but i could not fit anymore windings.

is it ok to jumble up the wires? can we establish a ratio to the windings? is it ok to use thinner wires to fit in more windings?

tikbalang

I made a  similar misstake
the windings you have tried look to me like they are for a ferrite toroid.
The CFL toroids are not ferrite .....they are probably powered iron.

Powdered iron requires more primary windings.

My best CFL toroid JT was made with 20 windings  of #30 magnet wire  4 strands  twisted together and wrapped on the toroid as one .

2 of those wires are used as primary  2  as secondary
Both sets of wires are connected start of one  to the end of the other.

This setup only puts out 1.6V according to my DMM but they seem to be very spikey volts......... by that I mean that the  impulses are very strong and the JT can do more than its indicated voltage would indicate.

This JT will light a 1W LED pretty bright.
It also lights a MR 16 light with 32 LEDs pretty bright.
This light also was all its original electronics.
This light will not light at all with 9V DC

gary