Joule Thief

[Mk1]

Sorry i had to http://video.google.ca/videoplay?docid=2000718611607454884&hl=en

[timmy1729]

Hey!!  I just hooked my new ferrite bead JT to my other toroid JT and both superbright leds light up very bright!  And, the JT (2nd one in the circuit) with the toroid is waaaay bright!  I think it is getting some cumulative (added) energy from being 2nd in line.  No pics yet and probably not for a while.

Bill

@Bill
I just tried hooking them both in series and parallel. I kept the big toroid JT second because I was afraid it would fry the small one. In series, the light on the small JT lit barely enough for me to see it had anything at all. The big one didn't light at all. 

In parallel, however, both lit fully! 
This is so cool! Both lit fully in parallel from the same AA! 
How many can be hooked in parallel and still work?

How did you hook yours up? I wonder if it had something to do with that Darlington transistor. The small JT uses a 2N3904 just like yours. I wonder if there weren't enough mA to power the big JT. 

[timmy1729]

Sorry i had to http://video.google.ca/videoplay?docid=2000718611607454884&hl=en

RIP George

[xee2]

@ Pirate88179

Hooking 2 JT in parallel is no different than powering each with a separate battery as long as the single battery can deliver twice the current required for a single JT.

[Pirate88179]

@ Timmy:

Check out my photo if you can see how I hooked it up.  Basically, I believe all I did was tie into the lead + from the bat on one end and tied into the - at the led - leg using jumpers.  As you said, I noticed NO decrease in the light output and these are high output leds.  So, the answer to your question about how many leds we can light in parallel is.....i don't know until we try it.  Do we need another coil for every led we add to the circuit?  Or, can we just add some more leds to the circuit and they will light just the same?

Keep in mind with the Fuji AA circuit and my 400 leds....they were all in parallel too, for whatever that is worth.

@ MK1:

I had missed your post on the electronic videos, thanks for mentioning it again.  Also, thanks for the George Carlin video, I am still watching it.  He will be missed.

Bill