Joule Thief

[Cap-Z-ro]

Heeey...I think I may have smoked some of that stuff back in the sixties.

[WilbyInebriated]

If its magnesium alloy you can light it up ,.Check this out
http://www.youtube.com/watch?v=sgzeGhd0adE

when i used to take my model t out to bonneville in the late 80's early 90's to run the time trials, it was a ritual there to light up a magnesium engine block... what a surreal sight at night on the salt flats, a mag block burning as bright as the sun. you could feel the heat from at least a block away. jet engines make good lighters

[Pirate88179]

Yes it does.  Also, I don't think you can put it out once it gets going.  Hence the mg fire starter blocks that I first used on my EER experiments.  Those will light a fire in the rain with wet wood.

Bil

[jeanna]

I am very sure that the magnet causes the core to saturate at lower coil drive currents. But I think that is just another way of saying the inductance of the coils is reduced. The coil will store less energy per cycle thus has lower inductance.

Hi xee2,
I like your explanation a lot.
thank you.
---
If I can stretch it even more by thinking of the pulses/sec (= frequency) over the wire substituting for joules/sec(=amps) inside the wire, I think it can help the others who continue to visualize this like a strange dc type circuit.
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@ArticKnight,
I made my first 2 joule thief circuits ON a magnet as you suggest. I/they worked for a week then stopped.
The magnet had temporarily put the transistor to sleep. I thought it was gone, but some time later after I had taken apart the circuit with the magnet, found it was ok I remember you were there back then, and even made a comment about it.

thank you,

jeanna

[jeanna]

  A torroidal transformer allows the primary current to be choked while still changing the magnetic field within the influence of the secondary. ....  ....

....  The impedance drops due to the core magnetic circuit and the current increases in the unchoked primary.

Sparks,
Maybe you are the person who can explain this to me.

Where on the hysteresis curve is "choked"

thank you,

jeanna