Joule Thief

[xee2]

@ jeanna

(still no comment from xee2)

I have not used more than one pickup coil. But I would expect that adding the two pickup coils together in series is the same as having one coil with twice the turns. Doubling the turns on the pickup coil does not double the pickup coil voltage but is unusually about 80% of double the voltage. So I would expect two pickup coils with same number of turns in series to be about 80% of twice the voltage of one. My experience is that frequency decreases as number of pickup coil turns is increased.

However, if both pickup coils are already on the toroid, then perhaps adding them together wil be close to twice the voltage of one pickup coil since you are not adding more turns on the toroid that way.

[gadgetmall]

@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

AS Mk1 and i said you corrected the PHASE !
what Transistor did you use . i know the gain of a 2n3055 is rather low .
and as far as mass of a toroid is concerned , it don't matter . I get extremely better results with beads and small toroid. just look at the tiny fugi AAA transformer . its output is very high and less than 1/4 inch . Its the Windings that matter and the phase plus the gain of your transistor.
Here are a few interesting oscillators  that look like Jts one of them will sing to you . you can build one and hook a small speaker up and hear your EB voltage change pitch !

Good Job

[xee2]

@ jeanna,

And the success came from the fact that I have switched the larger number coil out of the base coil spot into the collector coil spot.

@xee, I am glad to see you are here today, because this could mean an important modification to your theory... I think, anyway.

If you look at my diagrams you will see that I have always done it that way. No change in theory required.

[jeanna]

@MK!
I cannot understand those concepts yet. I have made a drawing that represents the primary in the jt I have on the biggo. It is not like either of those choices you gave me as far as I can tell, so...
Please feel free to change it and annotate it to explain, if you want to.

@xee,
Thank you, but
I didn't expect a comment about the pickups.

I meant the primary where the larger number of turns is on the base and smaller number is on the collector. and wow it is way bigger in output, but before on other designs or whatever... the opposite was true.
I knew you were working a theory about this. That is why I thought you would comment.

@Gadget
It is a 2N3055 It is printed with RCA on the front.

I corrected the phase?

thank you,

jeanna

[jeanna]

@ jeanna,

If you look at my diagrams you will see that I have always done it that way. No change in theory required.

Xee
I made a mistake in that paragraph.
I am so glad you responded. I have fixed it it should say:

I have finally had success with the 2N3055.
And the success came from the fact that I have switched the larger number coil into the base coil spot out of the collector coil spot.

No wonder you did not respond!!!

thank you and it is in time,

jeanna