Joule Thief

[jeanna]

@Bill

I contacted the supplier of the large toroids that Gadget posted a while back and asked for a quote on them.

Could you post this?
I must have missed it.
I have magnetics which made the tor-60, but I missed gadget's post??
jeanna

[gadgetmall]

I bet it is shorting somewhere.

First, I must ask if you tried just the jt part, and does that turn on the light in the basic jtl place?
Then If it does, I think you probably have over 1kvolts and there is a breakthrough somewhere in the insulation.

I don't need to remind you that the 30awg radioshack will do that but I have seen many scratches appear in the 27awg too.

If it is 2 volts the spark might be right at the beginning.

Is this a tor-60? or a look alike?

jeanna

Hi . Its possible it might be shorting . Its also possible i wound it opposite from the others. I have see this be a great big problem doing a hazens coil  I am using #26 from a 2500 ft roll I wound off about a 100 ft around a Popsicle stick so its easy to wind.. yes the first thing i checked was normal . Its bright  .They are the same toroid you have they came two to a pack on cardboard sealed up in plastic.They are Grey parylene painted with smooth tapered edges  ? I'll keep at it until i find what is wrong . Once i have it I'll Dunk it in latex rubber and let it dry .
Al

[Pirate88179]

Jeanna:

Here is the link:  http://www.mag-inc.com/home

I believe the part number is: 48613TC  (I believe XEE2 posted this number)

They do not show any pricing, you have to ask for a quote so I think this means they want to know how many thousand you need.  So, I asked for a quote on 4 and I also filled out a free sample request for 4.  We will see what happens.
I also think XEE2 said this was the "W" material.

Bill

[xee2]

@ gadgetmall

Hi Xee2 . I like you Design .I realize its probably Drawing 200 Ma with that low resistor but still its a start and a first i have seen . I wonder if yours will light two in series ? I think i double phased it by going over the first layer . DID you single layer or double layer  ?I used a diode and oled one meter had to change to a fluke with 2000volts max . getting a HV but no push .

Al

I think jeanna probably has the correct diagnosis - insulation punch through. Most wire is only rated for 300 to 600 volts. If your coil is single layer that is OK. But if it is two layers you will have wires next to each other with more voltage than that. With 400 turns I think you are over 2000 volts.

[jeanna]

I have read many explanations of the JT and I think all of them use the principal of core saturation. But I have been looking at the specs and started wondering whether the battery could in fact saturate the core before it saturated the transistor. And I believe the answer is no in most cases. I think this is why people have different results using different transistors without changing the setup. For instance jeanna's voltage increased quite a bit with a high current transistor, to me this shows that the core is not being saturated with low current transistors and thus the highest possible voltage is not reached.

I think you are exactly right that the max voltage is not being reached.

I came across this today in a search for the K thing.
http://info.ee.surrey.ac.uk/Workshop/advice/coils/mu/#sat

So, I think this is right but what we DO run out of... and fast is enough space in the middle of the toroid, which is why that tor-60 was so great. There is a looot of room.
I think the little tor-23 that I have been using since the beginning of this thread could make 1kvolts, if it were not for the center limitations.

jeanna

edit
thanks Bill. That is the same company.