Hi Guys

I want to do a JT for a science project for school.

I'm slowly reading this thread from the end to the beginning to try and get an idea of the best JT to use for my project... 

Any suggestions for which circuit and what winding config. could be used to light up fluorescent tubes using the smallest possible battery (to give a contrasting appearance between supply and output)?

Any help would be much appreciated.

SciMan

@ Gadgetmall

You need to try one of the eight inch round 22w cfl's for your Fugi.

They light a lot brighter than the 10w spiral cfl's
Even with the JT turned all the way down the light will still light.

I couldnt believe the differance in light off two batterys on my JT its almost full brightness.

@koen1

Show me a picture, also when testing different thing on the jt , i pre wound a pickup coil and rectify it so i know what is going on.
And yes only one pickup coil is not more , but many will see. But if you rectified your coil and tested many pickup coil and gone nothing,
Then your core is bad, change that.

Also what transistor and resistor are you using.

Mark

I found an interesting sealant for us - maybe not the least toxic, but it seems to be heat resistant to 1200 degrees.

http://www.rustoleum.com/CBGProduct.asp?pid=112

...Never thought about using a spray on enamel normally used on grills.


...And it comes in a few colors as well.  I'll have to give it a try in a well ventilated area.  Hopefully my coils never reach 1200 degrees.  This was available at Lowes.


--
The easiest CFL to use is one that you can buy without all the baggage - those 6" lantern bulbs...or the bend-abouts.

Quote from: Koen1 on March 10, 2009, 11:42:22 AM
yeah ok I won't be able to wind a 200 turn coil on those small ring cores at all, so I guess it'll
have to be a larger old transformer...

what gauge are you using and what is your toroid size ?
are your components specs Equal to the other member(s) you wish to replicate the work ?

Quote from: Koen1 on March 10, 2009, 11:42:22 AM
Any "back emf" effects seen in the JT should also occur in any other pulse fed trafo, shouldn't they?
So just hooking diodes up to the coils at the right spots should be able to pick some of that up...

back emf is only one side of the coin.
it as a conter part and the beginning of it exhibit the same behavior voltage wise, but in reverse.

Quote from: Koen1 on March 10, 2009, 11:42:22 AM
doesn't even matter how many turns you use on the JT core, as long as the basic two JT coils
have an equal number of turns.

not true, it don't need equal number of turns.

Quote from: Koen1 on March 10, 2009, 11:42:22 AM
Most claims of these pickup versions seem to include significantlygreater numbers of LEDs
lit with multiple pickup coils and some even include seemingly ludicrously high voltage DC output.
This is the part I have trouble with and cannot seem to replicate.
I just do not see much greater numbers of LEDs lit on my pickups, I see like one or two more in total...
I do not see enormous DC output, I see exactly what can be expected from the trafo and the input,
coming from a DC connection with a capacitor in parallel that retains a higher charge than the
feed current. That doesn't really show any excess energy or energy gain or whatever at all,
which seems to be in contradiction to what some of the guys here have apparently been getting out.
And this is becoming quite frustrating. People saying I'm on the right track while I just see
the same old dusty track I was on before... 

it is simple
with a ratio of 1:200, and enough milliamps, you should be able to light ~200 3v leds in series and more if you are using the .7 volt threshold ones.
do not see that as excess energy, it is not.
instead test how leds work at high frequency, theirs specs are given for dc, not for high frequency ac.
same thing for cfl, learn why and how they light.
to my knowledge, no one here gave measurements that prove energy gain.
most are only stating faqs or part(s) of it.
some with in between lines suggestions of further test that might be done, but that is as far as it goes.

i can confirm it to you.
there is no ou in a basic jt, with or without a step up transformer coil.