Joule Thief

[jeanna]

Xee2,

I was just trying to compile the information, but it seems inconclusive.

I found that using the DMM I had .985 v on the EB
but with the full bridge and the joule thief the Dmm across the EB leads said .768v So, I assumed the transistor was drawing around .2v and that is not enough to turn on the transistor.
I do not understand why it isn't getting to the circuit, because there is .985v and it is not using them.

I checked the voltage coming out of the bridge and it was .015v. so the bridge is not helping.
I will check in a few minutes , but it was not going into the circuit. I have the cap in place. This is the same cap Bill used. I also made sure it worked with a dead battery yesterday... .661v dead.

I am not sure what the problem is.
edit
I just brought it in and it lights just fine and the cap keeps it lit for 5 seconds with a 2 second hit of the battery.
I guess I will fiddle with the resistor to get the amps draw really tiny.

jeanna

[sm0ky2]

@ Jeanna,

i made the rectifier out of LEDs,connected to the secondary of the first JT. puts out about 14.5v
using the output to operate the second JT, which had many many turns on its secondary

cap charges to 60v after about 12 seconds.
removed the cap and shorted across it and got large sparks.

as far as i can tell the current drawing from the battery hasnt changed. though that doesnt make sense to me...
im confused about the whole thing myself.

strange things we're doing with a single cell battery thats near death...

i also should mention that the output of the second is rectified as well, LED diodes: one going in one side of the cap, and one going out the other side.

[resonanceman]

Do you have the schematic of how it is interconnected.
I posted one on the kapanadze topic.

Maybe you can help me with mine.

Jesus

Jesus

I   have not looked  at that topic ......
Here is a coincidence for you.

I  have been playing  with  a flyback transformer that  I  took out of an old monator   
I really wanted  to use  the core  from the transformer  to make a JT ............but the core  seems to be molded into the case .
SO ........ I  decided   to  try to make  a JT  with the transformer itself .

Looking  at the  pins  on the bottom ............ according  to   your  drawing   I connected  the  base coil  to pin1    The   wire that would go to B+  and the  2 wires from the coil that  are twisted together  is connected to pin  3  .
The  E coil  wire  is connected to pin 4.
The  output   ( secondary )  is  the high voltage lead comming out  of the top of the  transformer and  pin 10    If I remember right  pin 7 and 9  have high  voltage too .   I do not know if they  will  react as  separate  secondarys or  the same one .
I am  getting  113V  from  a AA battery .........not alot ..........but in the  range I was looking for.

Tomorow I am  going to  try  it with  a bit higher input  voltage .

The  power  this thing puts out seems pretty good .
I had been playing  with  a flyback / feedback network   earlier .
I   took  the JT out of that network  and  put  the  flyback JT in .....  My90 LED array is brighter ...........under load  I got  93.8 V across  the transformer ........after  a half hr I have lost .3 V

gary

[dllabarre]

I threw together a JT with components I already had. It turned on the first time   

2n3055
3 super bright clear deep red LEDs 2.5V Max, 25mA Max 110mW Max 3500mcd
3 super bright clear amber LEDs 2.4V Max, 25mA Max 100mW Max 5500mcd
5K ohm pot - I need to get a 1k for finer tuning.
6" x 1/2" diameter ferrite rod with 110 bifilar wound 22awg magnetic insulated wire

The 6 LEDs "look" the brightest at about 220mA @ 1.17volts.

When the POT is turned to extreme settings, left then right, the measurements are:
left: 47mA @ 1.27volts
right: 748mA @ .835volts.


How do these results fit in with what you all are finding?

Thank you,
DonL

[xee2]

@ sm0ky2

Just a word of caution, capacitors can explode if charged to more than their rated voltage limit.