Joule Thief

[Mk1]

Yes, I have a little machine screw holding a sort of soldered wire to the hole in place as the collector wire.
Why do you ask?

jeanna

To make sure there was not a mistake there , since the base need more turn on this toroid, did you see my post on two page ago , on attracting and repulsing mode.This could also explain the base coil.

Mark

[gadgetmall]

Gadget

That looks  great   

I am still  working at getting my  60 LED array  up to  full power .
What  was  the  numbers for your wraps ?

The best   ones  I have done  are clearly  in resonance ....... they hit  a sweet spot  and  the  lights get bright and the  current draw  drops way down .

The  problem with this is  it is not   stable .   when  anything  changes   a little   it drops out of the sweet spot.

Do  you have this  kind of problem with yours?


gary

I did not Count them It was a small yellow with blue inside toroid . a Power supply one . I just wrapped one wire around the whole thing then i wrapped another wire on top of that one all the way around . i would guess about 50t x 2 and it was so bright is smoked an led but i have a pot on it ! So i turned it down just a bit . Current consumption is nill and i bet i could light 100 with this one. I am have better luck just winding blindly than counting . I just fill it up and if i feel like winding more i do . i probably could put a secondary on top of the primary's ,looks like enough room to go another 50 with # 26 .Its still running bright since i posted this afternoon . It will probably run for  several days drawing 10 and slowly getting less as V drops . no problem with stability at all . its range is wide . i ran it with 15 k . the germanium has an hfe (gain) of 300 and volts .2 . i love these transistors . they always work with lots of windings and always go low on power consumption

BTW i got some Great News today . I am Officially RETIRED ! Thanks Obama

Gadget .

[Pirate88179]

Jeanna:

All of my toroid JT circuits (10 of them and counting) sing...some more than others but usually when under load.  All of my Fuji JT's sing as well and when they are under a very heavy load, I believe it goes up above my hearing range because you can hear it climb up.

Gadget:

Very nice device you have made.  Excellent work!

Bill

[jeanna]

@All,
Yesterday Mark asked about the frequency of the toroid and if the toroid output seemed to be best at a specific frequency.
So, today I have been thinking about that.

I am beginning to think this does not matter much.
Or if it does, if there is a fairly wide range for the effect.

With the exact same amount of wire and wound the same number of times but with different ones connected to the E and C, the coil began to increase its power to more than double the sum of the 2 halves.
Everyone may recall that the output was well below either half when they were connected in my ususal way.
So the increase from less than the output of one of the halves  to more than the sum of the the halves, occurred just by reversing the Collector and Base coil amounts.

(still no comment from xee2)

1 Half of the MK1 pickup = 90v,
together 2 halves = 60v - 80v (or ~12v) depending...
until I switched the b and c coils to be opposite positions.
Then the best output was around
192v
That was somewhere around
13.5KHz.

That was yesterday.
So, today using the "better" configuration but changing the transistor I get,
5 times one of those halves.
450v
I am amazed at the increase in output just with this transistor.

But, as the voltage went up the frequency went down. so this
450v is vibrating at a frequency of
4.16-4.5KHz depending on the led load at the bjtl.

So, I am not sure if 4.5KHz and 13.5KHz are in the same range. In fact it is the only range where the joule thief vibrates at all.

Maybe this is the resonant frequency range. ie. anything that allows the joule thief to oscillate might count as the range of resonant frequency. The physical mass as well as the material type of this ferrite core could be the deciding factors more than the circuit and its number of turns.

I think MK1 has been saying something like this, maybe.

I am going to remove the core from that stubblefield coil and see if it makes it resonate and output power more or less. I bought a cws ferrite bar that I intend to put in the center of that stubblefield coil but for now I cannot find it.

this will be interesting to see the differences between a coil with
steel, air, ferrite core. Same coil different cores.
Hopefully the 2N3055 can turn on with it...

jeanna

[jeanna]

Jeanna:

All of my toroid JT circuits (10 of them and counting) sing...some more than others but usually when under load. 

You know...
Mine never have, (I'm not counting the fuji which certainly does!) but all have been made with fairly small toroids and none of them are so slow as to be oscillating below 20KHz.

It has never occurred to me.
They were quiet because they were so very fast.

Thank you,

jeanna