joule thief won't work for me, can't figure out the problem



i made joule thief as shown everywhere in instructables, I tried few different transistors, and toroids, I had like 100 tries, and can't get it to work?

and: can I use transistors-in the middle of the last picture?


Picture of joule thief won't work for me, can't figure out the problem
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xtony666 (author) 7 years ago
i found out what was the problem-I bought 1k, and 2n3904,bc337,tip3055 transistors, and it works with all of them, toroid was ok
NachoMahma7 years ago
.  Can you post some clear, close-up pictures of what you have put together?
xtony666 (author)  NachoMahma7 years ago
uploaded, I'll upload more if necessary
.  All the joule thief schematics I found called for a resistor (often 1K) on the "B" coil. I don't see a resistor on any coil leads.
xtony666 (author)  NachoMahma7 years ago
sry for bad angle of the pic, it's on the middle leg of the transistor, and B coil, I don't know if it's 1K, anyway, can I use transistor on the last picture?
if still won't work, I'll buy pieces that are exactly needed and try, should work
Search Google for "resistor color code".
.  I can't read the numbers on the component in the center of the pic, so I can't look it up, but I'm betting that it is a voltage regulator, not a transistor.
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.  Did you try steveastrouk's suggestion (reverse one pair of windings)?
xtony666 (author)  NachoMahma7 years ago
i didn't, :S what do you mean reverse it?, i held 2 wires together and turned them around toroid bead

and does it matter which transistor I use, i used ones that look exactly the same as in other instructables, but dont know if they are NPN? - seems to me like it would be best to buy 2N3904 transistor like most people have


.  Let's call them coil A and B and the ends are 1 and 2. If the current connection is A1/B1 and A2/B2, then swap the wires on one coil so that you have A1/B2 and A2/B1.
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.  It has to be the proper polarity and you can't tell by looking at it. If the schematic calls for an NPN, it has to be an NPN. Do a search for the transistor number - 2Nxxx - and you can find out if it's NPN or PNP. I'd use whatever transistor the schematic calls for.
xtony666 (author)  NachoMahma7 years ago
ok thank you very much for your help, I'll try reversing, and get transistor I need
so I'm sure it will work
and then I'm going to make instructable (not for joule) but something with it(if that will work) :)

tnx
.  I wouldn't do both at the same time. Replace the transistor with the proper one; if it still doesn't work, then swap the wires.
Try reversing one pair of windings