Joule Thief

[resonanceman]

Hello everyone, i just joined as a new member on sunday night Australian time, my user-name is freepow,
I am attaching two joule thiefs that i,ve tried, both of these I used 2-AA i think, I could only measure just under 1 VAC with my digital multi-meter, should,nt it measure a good high VAC ??
I want to light a 240v - 4 watt fluoro with 1-AA, I dont want to use a disp-camera-circuit, any help with diagrams would be much appreciated, thanks.

Welcome  freepow

It looks like you have some experience building  electronic  stuff   sense  you  got  as far as  you did  before  asking  any questions


I will  try to  help     you with a few basics .
How many  of the  previous  posts have you read?

Like  Jeanna   I suggest using  the  2N3055   It  just seems to have more power .

As far  as   what  to start with ........  a  toroid  can work , but  I suggest  finding an old  TV or monitor  and  using the  core from the flyback  transistor .
This  core   is made for  higher power than most   toroids that you  will be likely to find ........and if you  wrap  the round   section    with   plastic or find the right size tube   you can  open  up the core and  remove the   coil  and  try again   with  very little problems


I  would  also  suggest  the   MK2 style  of winding  for the  primarys
At first  it may seem  a bit more complicated than   other ways   it could be wound   but  after  you do a few it is  very simple .
Also it is easy  and foolproof  to  connect .
Twist  the ends of the wires together on one side of the  core ........connect these to the  Battery +
connect  the other  ends to  the base and emiter .


I am  adding a couple  pictures .
The  first is   the  MK2  Winding  style

The picture shows  3 wraps   on each  leg .
With my  flyback transformer core JT  I  got  down to 1 wrap each side  for the wire going to the base  and  3 winds on each side  for  the other .
I suggest   starting   with  3 or 4 wraps on each leg .
Once it is  running  you can  fine tune it  ......
This picture shows only  what we call the  JT primarys


Pictire 2
Do   you  know  about  tank circuits ?
Sometimes   a  JT  will not work without  a cap for a resonant circuit .
This  schematic  is  the basic  JT  circuit  with  tank   that I use  ...... I should  add a secondary  to  this   drawing .

gary

 

[jeanna]

.
I am attaching two joule thiefs that i,ve tried, both of these I used 2-AA i think,
I could only measure just under 1 VAC with my digital multi-meter,
should,nt it measure a good high VAC ??

Your digital multimeter will not be able to read the vac.
It can only guess and extrapolate it from the dc it reads.
Plus it cannot read the very thin spikes at all.

MK1 has a description of the way to see what you are getting.
It should be on the circuits page that Bill put up for ease of reference.
You use a bridge rectifier and 2 additional diodes and a cap to collect all the voltage then you can measure it.

I want to light a 240v - 4 watt fluoro with 1-AA, I dont want to use a disp-camera-circuit,
any help with diagrams would be much appreciated, thanks.

I just bought a 48inch one for myself.
It might be easier to get an 18 inch 25w bulb to glow because it is the phosphors that are responding to the high frequency high voltage and not the watts.

You also will need over 450 volts output to light one so more than 200 turns on the secondary and maybe more like 300 turns..

BTW, how many leds IN SERIES can you light with yours?
If you can get about 30 to light in series you should have enough to light a tube.

Americans do not have 240 volts wall plugs.
The canadians and other australians here do.  (europeans too, but I don't think we have any europeans any more??)

have fun and check out the circuits page.

jeanna

BTW
your picture is

* jt 1&2.jpg (49.6 KB, 1481x1721

It is too wide.
Please keep pictures to 600pixels wide until stephan fixes this textwrap bug.
thanks,
j

[resonanceman]

freepow

Do you have  a program for  editing pictures ?
Your schematic   is very  wide .
It causes everyone  to have to scroll back and forth to read  all the posts on the same page .........sometimes  the affect lasts several pages .
I  use an image  editor  to crop my pictures so  only what is needed  gets posted .



I thought I would   add a little  more  stuff that might help.
The  first is  a schematic of  a Jesus  charger .
It   gives  you  a little  feedback .
Most of my  expermemts   deal  quite a bit with feedback
I connect  the  feedback to  the  ends of the  cap  in the  Jesus  charger .
The  first  picture is   a schematic  of  a JT with a Jesus charger .

I always  use  the Jesus charger .    I find   the  battery draw to be less when using it  and it provides  a quick easy way to connect   feedback .

The  second  picture  is  of my actual  Jesus charger .

The third picture is my flyback JT   
Notice   that    the   MK2 primary  is on the ends of the  core .....the  blue and white wires  still have the same number of wraps .  I ended up  with  1 white wrap  going to the  base and 3 blue wraps

This  JT  has  3 secondarys all wound together .
2 green #26 mag wire  75 ft each ......in  parrallel  these  easily   light a floro.
The  other secondary is #22 mag wire 40 ft
It  does not have the  voltage required to light  a floro. 

The  last  picture is my  flyback  transflrmer core JT powering   a 25 Watt  CFL at about half  brightness  and   a 90 LED array at about 1/4 brightness .
The 4 white  circles  below  the  LED array  are  coils for  flyback and feedback .
The black  square  above my  The  board  with  the  transistor  and pot  is  a 10uF cap out of  a microwave .
As you can see this is   being  powered by one AA battery


gary

[sparks]

In place of the led output has anyone tried to put a zener diode in series with a capacitor?  Then the capacitor could be used in a second lc tank circuit where the inductance of the lc circuit is the primary of a second torroidal transformer.  For every pulse going into the ouput tank you will get alot of pulses to the output transformer.  The input from the jt would then be amplified in the second oscillator.  Pretty soon there will be alot more current in the second oscillator than there is coming in from the jt.  The zener will act like a spark gap and only input power to the lc when the voltage is low or the power is being stored in the magnetic field of the second torroid.  When the magnetic field collapses on the output transformer it will recharge the capacitor which will start at a higher q because of the input from the jt.  You could take the output of the tank transformer and have it charge another capacitor through a zener and on up the voltage ladder until well insulation becomes a problem.  A good way to pull the power from the system without damping the oscillations is to wrap some turns around the wires between the capacitor and the torroid.  This forms a current transformer which will convert the current flow in the lc to current flow in an external circuit with minimal attenuation of the oscillations in the tank.

[the_big_m_in_ok]

sparks said:

In place of the led output has anyone tried to put a zener diode in series with a capacitor?  ... The zener will act like a spark gap and only input power to the lc when the voltage is low or the power is being stored in the magnetic field of the second torroid. 

@sparks
I had thought of that earlier in conjunction with an ambient atmospheric wire/capacitor system to charge a battery.
The zener would have acted like a spark gap, as you suggest, but without the radio broadband interference that comes with the spark.

--Lee