Joule Thief

[xee2]

@ Mk1

Very well done.

Power used by a resistor is given by ohms law as voltage squared divided by resistance. The resistance of the bulb stays the same from place to place but the voltage does not. It is easy to see that there is a lot more power going into the bulb where the voltage is higher.

In many circuits the voltage drops as soon as a load (resistance) is put across it. In your design, the voltage seems to remain high even with a load on it.

[xee2]

Modifying the TDK boards by removing blue caps seems to provide more output power, but it also seems to increase the input current draw beyond what a cell phone charger can put out. At least, for some reason the modified boards do not work from a cell phone charger. Note, the modified boards will light tube from a 6 volt battery.

[xee2]

Some TDK board test results. Note, the more power board is delivering the faster the sparks will be.

modified 6V -   http://www.youtube.com/watch?v=s1oIKAPyj4Q
unmodified 6V - http://www.youtube.com/watch?v=WGQSeFKxNyY
unmodified cell phone charger - http://www.youtube.com/watch?v=_LgIYrkx4TE

[resonanceman]

see image: ..since the collapse is in the opposite direction, it's actually proper to measure voltage like this..   

- - - - - - 

Does anyone know how to circumvent the cut-off voltage of the base; perhaps somewhere in the intricacies of the coil to base, the voltage can be boosted beyond the source? ( safely )?

I think  people  are making this  a little more complicated than  it is
A JT  is just a simple  oscillator  and a coil
The oscillator part  of the JT provides pulses to the coil
These pulsed  cause a magnetic  field in the  coil
When the pulse ends ........the  magnetic  field collapses and makes what   is called back EMF or a flyback pulse.
If  you  are using   a 1.5 V battery and  can measure over 1.5 volts  across  any part  of your JT you  are detecting back EMF.
No meter that I know of  is calibrated to read flyback pulses accurately
A diode bridge  can  be used to make  DC voltage from the pulses ...... but the best way to detect the flyback is   to use it to do something..... like light  a bunch  of LEDs

gary

Edit

Jeanna posted this link  a while back  but I thought that I would  repost  it and add a comment about it.
Everything he says about Tesla impulse technology applies directly to JTs ....... JTs make spikes..........impulses .......

http://www.youtube.com/watch?v=0aA8-0tctyw&NR=1

In the past some people here were trying to find ways to make their JT output  into a better sign wave....... what we should  be going for is  a  better spike





gary

[altrez]

I think  people  are making this  a little more complicated than  it is
A JT  is just a simple  oscillator  and a coil
The oscillator part  of the JT provides pulses to the coil
These pulsed  cause a magnetic  field in the  coil
When the pulse ends ........the  magnetic  field collapses and makes what   you  is called back EMF or a flyback pulse.
If  you  are using   a 1.5 V battery and  can measure over 1.5 volts  across  any part  of your JT you  are detecting back EMF.
No meter that I know of  is calibrated to read flyback pulses accurately
A diode bridge  can  be used to make  DC voltage from the pulses ...... but the best way to detect the flyback is   to use it to do something..... like light  a bunch  of LEDs

gary

Edit

Jeanna posted this link  a while back  but I thought that I would  repost  it and add a comment about it.
Everything he says about Tesla impulse technology applies directly to JTs ....... JTs make spikes..........impulses .......

http://www.youtube.com/watch?v=0aA8-0tctyw&NR=1

In the past some people here were trying to find ways to make their JT output  into a better sign wave....... what we should  be going for is  a  better spike


gary

Hello Gary,

I have tried to plug leds on the back end of the JT to find and or detect the back emf. What is the best way to do this? I cant seem to find a way to get it to work? I have plugged a led from the base to the negative post of the battery and it showed no spikes.

However I can read 4.5v on my Scope on the negative of the battery?

Any help would be a blessing,

Thank you.

-Altrez