Joule Thief

[kooler]

xee2
8 years.. awesome work..
this new core i got i can get it down to 5 ua.. without blinking a white led and is brighter than the ferrite core but any circuit below 5ua it just cuts off ..
you got any idea why.. is it cause the wires are a few mm away from the core..

does the pm's still work on this forum anymore..??


robbie

[xee2]

xee2
8 years.. awesome work..
this new core i got i can get it down to 5 ua.. without blinking a white led and is brighter than the ferrite core but any circuit below 5ua it just cuts off ..
you got any idea why.. is it cause the wires are a few mm away from the core..

does the pm's still work on this forum anymore..??


robbie

Well, you are better at tweaking than me. But my first guess is that more turns are needed on the base coil. If there are not enough turns then the reverse current will not be large enough to cancel the current turning on the base when the collector current is low (induced base coil current is function of collector current). There may also be too many turns on the collector coil - if the inductance is too high the collector current will not increase fast enough to generate sufficient current in the base coil (transformer coupling is a function of the rate of change of the current). Try using same number of turns for base and collector coils and use less turns for both so that collector inductance is not as high. If that works I am sure you can tweak it to get more collector coil inductance in order to get a higher output voltage. Good luck (good luck always helps).

[xee2]

Blinking Joule thief - some theory stuff >>  http://www.youtube.com/watch?v=LQinhM1CxkM

[freepow]

Hi  everyone,  need some help !!!

See attached picture first then read on...

Each Joulethief  drawing say about  150 mA each,  and I want to put one (Green LED) in the circuit to light up only when I switch one or more Joulethiefs on, in the circuit.

I cant put a green straight on the positive line because when I switch more than 1x Joulethief on, the current draw will be 150 mA for each Joulethief,  for example... If I switch on 4x Joulethiefs it will be drawing 4x 150mA = 600 mA's going through the green LED.

So does anyone have a clue where I can add the Green LED
I want to use the green LED to come on with a load, but I dont want a green LED on each seperate Joulethief !

[Pirate88179]

Hi  everyone,  need some help !!!

See attached picture first then read on...

Each Joulethief  drawing say about  150 mA each,  and I want to put one (Green LED) in the circuit to light up only when I switch one or more Joulethiefs on, in the circuit.

I cant put a green straight on the positive line because when I switch more than 1x Joulethief on, the current draw will be 150 mA for each Joulethief,  for example... If I switch on 4x Joulethiefs it will be drawing 4x 150mA = 600 mA's going through the green LED.

So does anyone have a clue where I can add the Green LED
I want to use the green LED to come on with a load, but I dont want a green LED on each seperate Joulethief !

This may not be correct so see what the others say, but I think you could place it just after your switch from the 2.5 v source, then, when ever either of the jt circuits are on, there will be a draw from the source and the 2.5 volts should light up the green led just fine.

Again, this may not be correct.

Bill