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My joule thief is not very bright? Answered

My joule thief is not very bright? I've changed the windings, transistor and the resistor; and it is still pretty dim. Help please Parts: 2 different size toroids: Large and Small 3 Transistors: 2n2222, 2n3904, 2n5830 2 Resistors: 1k, 2.2ohm blue led white led with a heatsink Also I used a 20awg and 36awg to make the toroids

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steveastroukBest Answer (author)2009-10-01

I suspect you simply haven't got the energy available from the battery driving the Joule thief, nor have you got the current handling you need - close to 300mA. A Joule thief is a very neat thing, but it "cannae brek' the law's o' physics" to coin a phrase.....

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daemonral (author)steveastrouk2009-10-01

Thank you, I think I understand.

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steveastrouk (author)daemonral2009-10-01

Try feeding it with a good low voltage supply. A 'C' or 'D' cell should do it. Try using a thicker wire on your windings. The transistor can handle up to 800mA, but the gain will fall off as your collector current increases. Try and Change LED. Use a red one. Make some measurements with an oscilloscope. Steve

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steveastrouk (author)2009-09-30

You SAID its very bright, how can very bright be very dim ?

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daemonral (author)steveastrouk2009-09-30

I'm sorry I meant to type dim I must have blanked out

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steveastrouk (author)daemonral2009-09-30

What's the LEDs rating ? Steve

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Joe Martin (author)2009-09-30

Have you tried a different battery?

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daemonral (author)Joe Martin2009-09-30

yes, I have changed to a new battery.

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lemonie (author)2009-09-30

Pictures, parts, specifications and a circuit diagram would really help here (otherwise people are just guessing). L

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