Joule Thief

[guruji]

now climbing to 1.276V.
the battary NI-CD AA700mAh recharge itself !!!!!!!!!!!!
I cant belive my eys. all parts from tv, from skip. I have only multimetter, breadbord and soldering tools.
I cant ajust properly it, but its gooooooooo

Hi Tysb3 thanks for sharing what transistor you're using?
Thanks

[xee2]

I graphed some data from JT I have built. It seems like there is not much point in using more than about 150 turns. I plan to add another data point at about 150 turns. I think this would be a valuable thing for jeanna to check me on. She is good at catching my mistakes. This data is with 2 base and 10 collector turns and a 2N3055 transistor.

EDIT: This result may be due to not having enough battery current. I wll try to test that.

EDIT: Using 2 D-cells and a 10,000 uF capacitor in parallel for a power source pushed to voltage with 250 turns up to 701 volts. So there is some performance limitation due to battery current, but not enough to be the main cause.

[broli]

xee2 have you tried a higher current rated transistor? I think jeanna's big succes has to do with this, more current = more magnetism = bigger collapse. That is if transistor gets saturated before the core does.

[xee2]

xee2 have you tried a higher current rated transistor? I think jeanna's big succes has to do with this, more current = more magnetism = bigger collapse. That is if transistor gets saturated before the core does.

Yes. More current will produce higher output voltage until something saturates.

This was a test of voltage vs turns with everything else constant. Not a test to see how much voltage I could get. The point is that it seems like there is a diminishing return for adding more turns.

EDIT: I know I can get over 1000 volts out using the toroid and the same transistor, so I do not think these test results are due to saturating the core or transistor. But, I also do not understand why the voltage is being limited. In a normal transformer the voltage keeps increasing with turns until the core saturates. I had expected that to be the case for the JT also, but it does not seem like the JT works that way. Of course my data might be bad.

[tysb3]

@ guruji
transistor is D1885 from tv's line transformer