Joule Thief

[Groundloop]

@xee2,

The oscillator is close to an Hartley oscillator. It is a low waste
configuration because the base current is "recycled" through
the power coil. So it is easy to get close to 100% efficiently
with this circuit. If I increase my output coil to approx. 700 turns
then this circuit should (in theory) be able to light up a string
of led bulbs. But my goal right now is to see if I can get some
ferromagnetic resonance in the Ferrite core, and see if this
resonance does anything to the delivered output power.

Attached is my next try. I will use some diodes to clamp down
the transistor and give the high voltage spikes some path to
go. This will probably protect the transistor from blowing up.

[EDIT]
I have tested this circuit now. Now I have a "well behaved" circuit
that runs stable and the transistor does not blow up. But I also lowered
the efficiency a lot. Needs almost 2,5 Watt to fully light the 1,8 Watt LEDs.
Not good. I can also see on the spectrum analyzer that the circuit no
longer is a wide band oscillator, as it was.

GL.

[Groundloop]

Hi,

This circuit is better but still waste too much power.
I need 2 Watt to fully light the 1,8 Watt LED bulb.

GL.

[Groundloop]

Hi,

I have tested this circuit. I did use a function generator
and tried all frequencies from 0 to 5MHz. Did not detect
and change in the output from the circuit. Next test will
be making an extra coil for the function generator input
and test again.

GL.

[Groundloop]

Hi,

I have wired up this circuit. The first thing I noticed when I
connected the high voltage to the Ferrite core is that I got a
low light output in the LED lamp EVEN WITH THE CIRCUIT
POWER SWITCHED OFF!

Next thing I did was to switch the circuit on with a low
input voltage (10V @0,08A) and then switched the high voltage on.
The LED bulb light did get dimmer with the high voltage on.

The research goes on.........................

[EDIT] The LED bulb lighting up with only high voltage was due to
           dielectric leakage between the Ferrite core and the coils.

GL.

[powercat]

Hi GL,
If you can get close to that 100% Try feeding the light energy into a solar cell,
it has been tried before on this thread some time ago, to many pages now to find it

Also there is a new thread where this is already being tried
http://www.overunity.com/index.php?topic=11686.msg305277#new
Vid
http://www.youtube.com/watch?v=i5K11dCgulY

all the best
cat