Joule Thief

[Mk1]

@jeanna

You got it,now that you have connected the pickup coil to the bridge and the + and - (the one not used) are like a battery you can now check that voltage with your voltmeter or connect leds to it.

[jeanna]

Thank you xee,

In this case the resistor is connected not to the led but to the base of the transistor. The led is parallel to the c nd e of that same transistor. No other resistor is used, to my understanding. (not in my jt's)  I have seen various explanations. None of them predict this lighting we are seeing. And, you seem to understand why my led turns off when the 2-y is added.

I appreciate your help.

I am not sure it is too much help. I think I wasn't asking my question very well. I am grateful for all of it.

But, you really ought to build one of these,  I thought you had.

I still am planning to try varying the number of turns in the 2-y. In fact I am winding a new jt right now for use with a breadboard. so I can make multiple changes.

@MK1

OK good. I finally understand. I am making a DC source like a battery.

Thank you.

jeanna

[Mk1]

@jeanna

I just got the same problem you had lighting the led of the pickup coil and the jt at the same time , i fixed it by changing the led polarity Always make temporary check of the led before soldering that will help you greatly in understanding what goes on in this circuit.Leds are like diodes like in the video the juice only pas one way,it may light even if not connected in the properly if voltage is ac(in this case the led working is not a indication that its connected right).

[electricme]

@ gadgetmall
Torrids do attract a magnet, weather they are working or not.
I wanted to see what was going on inside a JT when it was working, so I connected the cro to it (on the output) and watch the waveform as I brought the magnet towards the torrid.

The waveform began to diminish in size, the closer the magnet got to the torrid, eventually it extinguished the output of the torrid, and the LED extinguished.
Now that effect occured on my small tiny torrid, which was my first JT.

On my 2nd bigger torrid, I did the same experiment. (using the same magnet).
The output fell, the LED dimmed, but didn't go out entirely.

There are many variables here, different sizes of torrids, different strength magnets etc etc so this experiment I did only confirms that a magnet does cause an effect, on the output of a JT, but it dosent make the result set in concrete, if you follow my meaning.

@ jeanna
Sorry about leading you astray by my not putting the AC and + & -  symbals on my diagram, I expected everyone reading it would know, So my apology to you and anyone else who makes this mistake, and I also have learnt a lesson.

I will repost my diode setup with coloured wires with a simple hookup setup to show you.
RED = Positive (+)     BLACK = Negative (-)   YELLOW = AC (~)

Diodes come in many amazing shapes and sizes, and have different purposes.

@MK1
I think the trouble I am having with my tapped primary torrid coils is I made the primary with toooo many turns.
To test this, I will supply it with 12v AC, then see what happens at the secondary.
If the output goes way up, then I will be correct, then I will have to make another torrid, I am not going to pull this one apart.

jim

[Cap-Z-ro]

Re: Magnets effect on toroids.

Has anyone tried holding magnets arranged in opposition or attraction either side of the toroid ?

Regards...