Joule Thief

[xee2]

@ Pirate88179

I think your one inch toroids are the same as some I used a few years ago. I was able to get over 50 volts out using only 20 turns in the following circuit with one AA battery. If you use 200 turns you should be able to get over 100 volts out which should be enough to light one of your 100 LED Christmas strings. May only required 50 turns, but since I have not tested it I put 200 to be safe.

[electricme]

@ all
It is SKOOL time  and today we will learn how the humble diode can be put together to make a simple Bridge Diode.
You will need 4 diodes, they could be geranimun or silicon ones.
OK AC forms a sine wave, which goes upwords and downwrds (my ADHD playing up again), and this goes on as long as the AC is there.

What we need to do is to "rectify" this stuff going up and down to make it go stright out.
Take a look at 0246.jpg photo.

Get four (4) diodes and lay them out, see photo 0247.jpg and look at 0249.jpg also

Pick up a diode, place it in your fingers like you see in the photos, grab another diode and do the same, make sure you put the "silver" bar at the end of the diode the right way, then twist the ends together.

Now pick up another diode, look at the photo again, twist the end to the diode you want to join it to.

Look at your 3 diodes, double check the diode arrangement is the same as is seen on the photo.

Pick up the last diode, and place it between the last 2 ends that are free, have you got it around the right way, double check.
Twist its leads together.

OK Tripple check your "Bridge Diode" you just made, does it look the same as the one I made in the photo?
If it does, good O,  you have a bridge that can do whats a full rectification of a AC voltage.

You could buy a Bridge Diode ready made, but wheres the fun in that? you wouldn't learn. ha ha.

OK, this bridge diode you can now use in your JT you made up, so you can do something else with the power except light up LEDs.

SKOOL is out now.

CAPACITORS is next lesson.

jim

[jeanna]

@MK1,

I guess I need to sleuth this out.

I re-made my joule thief last week when I blew it up on the AAfuji camera ckt.

I also upgraded it to white light. It works very well. So, that isn't the problem, I am sure.

The new light on the secondary-pickup is lit beautifully.
The voltage across the 1Kohm resistor is 0.56V to the base of the transistor. (2N2222)

Good morning all,

I see jeanna has provided a nice diagram,

not me, but I agree a very nice diagram.
I think MK1

... however I thought I might add a little to it also.
How to actually make a bridge diode from discreet diodes.

That would be great. Please do.

EIT: I see you did, thank you.

Jeanna, the LED connected to your actual JT should lite up, this is to give you an indication that it is working, but its main purpose is to help in frequency control of the JT.

Hmm, Its helping in the frequency control? interesting. Well that part must be working, since the secondary is making the led light up. 40 turns around and only connected to itself. I like it a lot. I plan to add a few more.

The transister has an internal diode (as well as other parts) but its main function is to cut the current to the coil, so the collapse of the magnetic field in the torid will be picked up by the secondary coil of the JT.

I understood this. It acts as a switch. I suppose it is some horrible differential equation that helps to calculate what to expect... but this is new, isn't it? maybe we need to make up the math to describe it!?!
I am curious to know what to expect  from changing the resistor.

So, I will be making a new one with a couple of variable resistors so I can watch what happens.

Take a look see at ISTs utube videos, particually the one that has the see through relay chatting away merilly, this should give you a clue.

Unfortunately, because of international licencing laws, Flash is not available on the xo laptop. I will have to  wait until my mac returns home to watch any youtube videos.


Thank you both,

jeanna

MORE EDIT,

@xee
What kind of capacitors do you use in this application?
I have made the wrong choice too many times to not ask.

thanks

[electricme]

@xee2
I made a mistake about giving gredit to jeanna for a post, It was you who posted it.
Sorry xee2

jim


@ jeanna thanks for pointing out my mistake, I put it right, TA 

@all
jeanna is getting confused with capacitors, and I agree with her, they can be awful to sort out especially the ceramics..
So I did a swift google search and came up with 2 web sites

http://www.justradios.com/uFnFpF.html
http://www.radiodaze.com/capacitor_ID.htm

Just print them out and hang on the wall of the tech work benchs.

@MK1
I went back a few pages (end of P87) and took a look see, thank you for posting this for me.
I think I got it now, your JT setup should be, lets seeeee.

JT1 has blue & green wire
JT2 has red & yellow wire

Output coil 1 is wound in golden wire = 48 turns
Output coil 2 is wound in golden wire = 48 turns

But, all this shares a single torrid bobbin, am I right? and is this the reason you have mentioned about it must be "tuned" for efficency?
I think so, or one section will overlap the other and nullify some of the output.

Interresting.

One last question, in the jpg, I can see 2 x vertical black thingies, are they ceramics? if they are, I have only seen the white or yellow ones.

jim

[xee2]

@ jeanna

I use ceramic caps for most things. The part numbers usually stat with "CK".  Ceramic caps are not polarized (either side can be positive or negative) and they are pretty indestructible. If you use tantalum caps you must be careful of polarity and the voltage across them.

Resistor controls current transistor uses. Lower resistance equals more current.