Joule Thief

[gadgetmall]

Nice

all done this one turned out nice .... 

ist!

added a close up of my coil

Nice . Wheres the tap at  ? I love the Smell Of Solder in the Morning 

[xee2]

@ gadgetmall 

so the secondary is out on this design

I suspect that you still had the LEDs connected to the collector and that the secondary will work if you try it without anything connected to the collector except the toroid. The Fuji board gets its output from the secondary and you said it worked. When using a secondary, the collector should not have anything other than the toroid connected to it in order to get the highest secondary voltage.

[timmy1729]

@ timmy1729

This is how to hook up the transistors for a Darlington Joule Thief. Note that the base resistor will have to be larger since the Darlington pair has a larger gain than a single transistor. I do not know what value will work, I have just put 10K to show it needs to be greater than 1K (it may need to be as high as 100K). Also the circuit will stop working at a higher battery voltage (about 1 volt instead of 1/2 volt) because the voltage needs to be high enough to turn on two transistors junctions.

EDIT: I do not think there is any performance advantage produced by using a Darlington transistor. But, maybe your experiments will prove otherwise.

I can't remember if I've responded to this or not. *NOTE* If you take or ever take an antidepressant for ANY reason, do NOT let yourself run out and have to stop cold turkey. It is NOT good!

Anyway...
I have a TIP120 Darlington on my bigger JT and it gives me double the voltage without dropping the mA's too much. Using two separate transistors in a Darlington setup gave me less voltage, so I stuck with the TIP120. I have a TIP3055 that I'm going to try out 

[timmy1729]

I have just reread in my electronics books about this.  Three legs is not a variable resistor, it is a potentiometer.  As you can see on my latest video from a few days ago, I too used a pot as a VR.  This is done, according to my books, by using the wiper and one of the other legs.  If you use one, the resistance goes up as you turn CCW.  If you use the other leg, the resistance goes down as you turn CCW.  (and visa versa)  Variable resistors have only 2 legs but Radio Shack did not have any so I used a pot.  If I am incorrect about this, please, someone let me know.  This is what my books say however.

@ All:

Thanks to everyone involved here on reaching the 200 page mark!!!!!!!  Over 2,000 posts and we are still going.  I still have to go back and catch up from a few pages back.  My old cat (15 years) is very sick and I have been working with the vet and taking care of her most of the day.  This is indeed a landmark and I appreciate that it was noticed by those that posted about it.  Once again, to all of the experimenters and posters.......a real big THANK YOU.  You all are great!!


Bil

Take care of your cat. We'll hold down the fort  Give her some extra catnip as a get-well from all of us 

[timmy1729]

"Can you post how you hooked the JT's up for one to power the other?
- Just make two (or 3 or 5) and connect each following instead of LEDs.

Nothing happens here till we get amperage...

Could you be a tad more specific?