Joule Thief

[jeanna]

@jeanna
Here is a couple pics.. ...
....
I bought some 50k Pots today.. but i cant figure out how to get them to work? Is there a link somewhere?

I love that battery holder.
Also, I never thought about putting all the parallel lights on the battery rail. It would have saved me a lot of time a couple of months ago... so, thanks for those pics.

A pot has 3 legs.
Put your meter on ohms. Now, touch 2 of the pot legs and find 2 that say something other than the maximum. Usually a center one is involved with the outside legs being the maximum. When you find them, clip some alligator clips on longish wires to those 2 legs. While watching the ohm count on the meter, turn the little screw in the center of the pot and watch the number of ohms change.

I usually bend one of the unused legs out flat so I don't get confused when the thing is set in place.

To change the resistance just turn the pot screw until the lights get to what you want them to be, then pull out the pot and measure the resistance. (You can't measure resistance with the battery connected to the circuit. ) So, you can measure it in place if you remember to take out the battery and if you can reach the legs.

I am getting tired, I hope this makes sense.

jeanna

[Pirate88179]

@gadget Ill pick some N3904's up tomorrow.

@jeanna
Here is a couple pics.. i am testing using 15 whites right now just to see how long it will last.
http://www.postimage.org/image.php?v=Pq21aVJ0
http://www.postimage.org/image.php?v=Pq21a_Ii
http://www.postimage.org/image.php?v=Pq21b4HA


I bought some 50k Pots today.. but i cant figure out how to get them to work? Is there a link somewhere?

@ Dog:

50k pots are probably too much for what you are trying to do.  I use 5k and even those are too large with the 1k base resistor.  It will work, but you will find that your adjustment range of turning goes from like 320 degrees to like 4 degrees.
Pots are simple.  There are 3 connections, the one in the middle is the wiper.  Just attach your wire in series with the base resistor to one of the 2 side connectors.  Take the line out from the wiper which is in the middle.  If you put your meter on the pot before wiring, set it to continuity setting, and as you turn the pot you will see that one of the connectors to the wiper will increase resistance when turning clockwise and then, the other will decrease resistance when turning clockwise and visa versa.  Just use the meter and it will be obvious to you right away.  Others here know more about this than me but, that is what I know. Nice pictures man.

Bill

[electricme]

@ Bill,
Congradulations, the Forum is at 500.
All the best for another 500 whacko posts
jim

[Thaelin]

   500 pages at 10 posts per page, that makes it 5000



Going to set a record here folks.

thaelin

[dog812]

Thanks for all the help. I guess ill try to return these 50k pots and get some 5k's..
I am also going to try some 3904's and see if that makes any difference compared to my n2222. And i guess ill be buying a cheap voltmeter.. make this a lil easier.

Well these 15 LED's have been lit off 1 rechargeable AAA battery for 12.5 hours and still going..
It has already almost doubled the time of a normal JT.