Joule Thief

[Pardon]

@Jeanna the no load meaning is no connection but just measuring the battery voltage. and i am using a salvaged 3/4 inch black toroid from a computer supply. so far it's my best one.

@Electricme your welcome for the information. if you or anyone finds any problems with it feel free to change it and make it better. reading it myself sure cleared up how JT's work.

@ Mr Mag you may be right i my self do not understand but what was written sounded like what i am seeing with the circuit i posted, plus it makes since to me.

@Gyulasum yes that web site is where i copied the transformer information from. but i did not get all the information he had posted on his version of lighting a led. after all he uses 2 transistors at 80 ma and 1.2 volts. and after adding some tuning parts he gets his circuit down to about 20 ma draw


@Gadgetmall thanks i guess it is very much like the one you posted. thanks for pointing that out i really didn't realise it until you let me know. wow your ckt was one i wanted to build so i am going to update my ckt to the one you made. thanks again

@all i only posted my version of the ckt  because some one had said their ckt blinked and they said they didn't know why or how they did it. well i did the same thing and i wanted to know how to make a jt blink so i found that if i changed the resistance to a higher resistance and added a electro cap i could make my ckt blink.  then i found the transistor information so i posted it because i could see what was being explained was happening in my ckt. and with my own eyes and not with a scope. if that makes any since.  so now i have a strobe light JT.

[jeanna]

Hi everyone,

I have a question. I am wondering where is the ground in a jtc? And, could it be that one is needed? The battery is not the ground once the circuit goes into the secondary.

The reason I am wondering this is because I have noticed that when I touch the secondary with my hand in any way, the scope often shows well over 100 volts. But without my hand it might see only 30volts.

Remember this is NOT a plug in scope, so there is no AC from the wall and no ground from the wall to confound this. (Or help if it is needed.)

I don't know what capacitive coupling is, but I know people get told that is what does interesting things that don't count, like make the fluoro go on etc. So, I wanted to be sure I wasn't making capacitive coupling happen, so wandering in the dark, so to speak, I pinched the secondary with the metal pliers and put it on the table and let go. 114volts. But when that is not attached, 32 or 12 volts.

IF there is a "normal" explanation for this, would someone please give it?

Do you suppose a ground is needed on the jtc when the secondary is functioning?

thank you,

jeanna

[jeanna]

Yeah,
I just tried another one.

115v on only one secondary wire makes this my best jt toroid.

I clipped a 24 inch alligator clip to the other side of the wire while the scope was reading it, and let the clip rest on the floor, and the volts shot up to 237v.

Maybe I am the only one that missed this, but if not... there it is!


jeanna

[jadaro2600]

hmm, interesting, perhaps it's the magnetic fields of the earth and the generated flux that are reacting to one another?

A dimple in the ambient field.

[xee2]

@ jeanna

I clipped a 24 inch alligator clip to the other side of the wire while the scope was reading it, and let the clip rest on the floor, and the volts shot up to 237v.

Where are your scope probes attached? Try taking the 24" lead and touch it to various parts of the circuit. It would seem that you have a higher voltage somewhere that is coupling to the lead.