Joule Thief

[crowclaw]

@ Jeanna

It's possible the RF radiation plus any localised static discharges could have a damaging affect here. As I have said many times the pulse energy produced can be far reaching from these oscillator coil combinations, which can have a high harmonic content towards saturation and performance instability, hence the spikes used within your projects. It's possible the PN junctions could have become ruptured. Try making up a grounding plate so all the device legs share a common ground while in store. You can also do some comparable gain tests on your devices between old and fresh stock. Equipment that is not in use often escapes these type of issues, as the devices are not OPEN or unconnected. With the progress you're making you could well be generating mini electro_magnetic shock waves!!! (joke)
Merv

[stprue]

This was in the TPU thread!  Has anybody tested this JT variation?

http://video.google.co.uk/videoplay?docid=-1815461677597553845&ei=S6c6S_aPDs6z-AbGhuAc&q=tpu&hl=en&view=3#

[gopalyajur]

Hello Everyone,

Hope you all had great Christmas.

I have been following the thread for a pretty long time and did learn a lot from
everyone here. I was busy with my thesis for a while and did not have enough
time to build a HV Joule thief until recently. My Joule thief is putting little more than
1800 V A.C (i would say spikes) with the following configuration

2N3055 transistor
1.5 inch toroid
base winding - 4 turns
collector winding - 9 turns
3 layers of secondary - almost 500 turns with 26 # winding
1K pot to control the base current

with all this my CFL (11 watt) only shows a faint glow.

I dont have a camera now, will try to post some pics later.
And would check the scope readings when am back in the office.

In the meantime can someone let me know why I only have a faint glow

is it the frequency??

Anyways wishing you all a HAPPY AND A PROSPEROUS NEW YEAR!!!!

Regards

Gopal.

[innovation_station]

here is a picture of todays adventure ...

i decided to make a nicer board and i removed the bulky connectors  used smaller ones

ist!

added 2 25 ohm stats

i know i know your saying jesus ist! look at that thing ...  lol   beleave me i know !

[jeanna]

. My Joule thief is putting little more than
1800 .... spikes with the following configuration

2N3055 transistor
1.5 inch toroid
base winding - 4 turns
collector winding - 9 turns
3 layers of secondary - almost 500 turns with 26 # winding
1K pot to control the base current

with all this my CFL (11 watt) only shows a faint glow.

is it the frequency??

Hi gopal,
Welcome to the joule thief thread.
Thank you for providing the important information.
(We love real experimenters here.)

First... yes 1800 v spikes.
the way we abbreviate the numbers here is this way for yours:
4T,9T,500T

wow, 500 turns! I am impressed especially on a 1.5 inch toroid! I would never have guessed that you could get that many turns onto this with #26 wire.

Anyway,
It is possible that the frequency is down with that many volts.
Sometimes putting a neo magnet onto the toroid helps to raise the frequency.
Is there a squeal?
CFL's can be hard to light, but I would not have guessed they would be hard to light with 1800 volts.
Maybe what you call dim is what we are all getting?
The only way to answer this is to do a little experiment with 2 identical cfl's.


Turn the jt cfl on -so it is already on.
Arrange yourself and the lamps in such a way that you can see both bulbs at the same time, so put the jt cfl in front of the regular one.
     [You will then turn on the other one from cold.
     This means it cannot be on for 30 minutes and is completely cold.]
Now, looking directly at the dark bulb turn it on.

That first cold instant is the only time you can make a true comparison of the light.
As soon as the regular light is on it begins to warm the bulb and the light increases dramatically.

I think it would be worth a lot if someone could figure out how to add some capacitors with resistors in such a way that the jt cfl will get warmer, because then the light will be equivalent.

Thank you for joining this group,

jeanna