Joule Thief

[innovation_station]

Hmm, this circuit (a very basic transistor oscillator with an inductive coupling) is called "The Joule Thief"? Lol,  I can assure you it's more like a "Joule waster"...

Yes, it works with only a few (easy to get or make) components, but that's about all it can do...
It actually works as a (quite inefficient) DC to AC/frequency converter, wasting at least half of the Energy available.

Maybe it's the rather low input voltage where LED is still working that fascinates you?

There are serial (three/four pin "transistor like") components on the market, which allows you >85% efficiency (DC/DC chips, usually needing only a few external low-tech components to work). They all beat this circuit (in efficiency) at least by the factor of two... And they're still not Unity.

Joule Thief? Yeah, sure...

fool yea sure...  i bet u are   do you get paid to do what you do?

it works and whos fault is it if YOU DONT UNDERSTAND!!!   WHY IT WORKS....

lieing through your teeth  EH!!

you can run on for a long time ......  run on for a long time ........  sooner or later gotta cut you DOWN! 



IST!

well i guess i will have to make a little test ......

i have 2 24 led rings....   they run off 4 aa batteries each....    i will install a jt in 1 unit  and we will mesure the run time from 1 battery......

and we will in the other unit just let it run with 4 batteries  and see how long it runs ....

as tesla stated time is gained.....   DOES THAT MEAN RUN TIME.....

[spinner]

ummm... thanks Captain Obvious....

the serial component you speak of are not more efficient, and for sure not by a factor of 2, as tested here...
http://www.talkingelectronics.com/projects/LEDTorchCircuits/LEDTorchCircuits-P1.html

Yes they are. 
Why would they (manufacturers) lie about it? Take, for instance, PR4401. It's efficiency is declared under certain conditions, and it can provide a continuous power at #82% (ENERGY EFFICIENCY)!. Try to adopt the circuit discussed in this thread to the same conditions (add rectifying/smoothing, etc..), and see how it will perform....

Or, take a two identical supercaps charged to the same Voltage, and see how long the LEDs will work  with both circuits.... Or, find an equivalent serial ic circuit with a PWM output capability... Or,... Whatever...
You're aware that we're comparing a +50 years old electro-tech components against a few years old? I'm sure there's at least some improvement being made....

BTW, Thanks for providing the link... It is a good text, telling a lot about LEDs and suitable LV driving circuits...

As you may have noticed, the author never claims OU. And the only efficiency he's talking about is based on a "personal" light intensity perceptions (not correct measurements). Need I say more?

all that aside, my JT lamp uses 3x2 led's 3.3V 19mA each. 310mA drain @1.5V (81%)
now if you buck it instead of boost, and feed the "extra" V back to the smoothing capacitor, gets you closer to 90% efficient.

Thanks.. Can you provide a circuit schematics and description/details of a measuring procedure?
The "extra smoothing cap" ALWAYS lowers the combined circuit efficiency... Voltage without current cannot do much work...

OK, i admitted before that we're "not looking through the same glasses"...

Cheers!

[innovation_station]

i appolige spinner

i dont mean to be rude bro

i want my point across properly ... 

this is one of the simplest cavatition devices....   ever




once understood

well

ist

[spinner]

fool yea sure...  i bet u are   do you get paid to do what you do?

it works and whos fault is it if YOU DONT UNDERSTAND!!!   WHY IT WORKS....

lieing through your teeth  EH!!

you can run on for a long time ......  run on for a long time ........  sooner or later gotta cut you DOWN! 



IST!

well i guess i will have to make a little test ......

i have 2 24 led rings....   they run off 4 aa batteries each....    i will install a jt in 1 unit  and we will mesure the run time from 1 battery......

and we will in the other unit just let it run with 4 batteries  and see how long it runs ....

as tesla stated time is gained.....   DOES THAT MEAN RUN TIME.....

Ahh...Ohh.. Geee, thanks, IST!

I feel honored, I finally got attention from the top FE scientist, and the most productive inventor of all times!

Yes, majesty?

Oh, please please please, let me understand....

[innovation_station]

Ahh...Ohh.. Geee, thanks, IST!

I feel honored, I finally got attention from the top FE scientist, and the most productive inventor of all times!

Yes, majesty?

Oh, please please please, let me understand....

now your being an ass

why?

do you think this sh!t dont work....   

hummmm   i must laugh .... 

how much power do you want 

lol lol !!!


ist

walk the path .....   or pave your own....  im still walking.... my path