Joule Thief 101

[resonanceman]

As I see it  one of the  problems  with  using  toroids  is the big ones are relativly rare .

A way  to get the job  done with what is commonly available  is required.

I will  try to explain  a way  to use  a group  if small  toroids in  place  of  a larger  toroid

The  picture  below is of several of what  I call  candy cane  coils.
Why I chose that name  is not evident  in this picture.
When smaller  windings are  used  the  windings spiral  around the the  toroids  like the stripes on a candy cane.

All  the   toroids  in the picture  are wound with 20 wraps  of  cat5 twisted pair.

All of the  toroids  are wound in the same  direction.

I chose 20 wraps  because that is all that will comfortably  fit on  this kind  of toroid  with this kind of wire.

The  primary  for each of these  toroids is 4 wraps through the centers of  all the toroids
4 wraps  seems best  for  all the  5 for $1 toroids  I have tested so far. I am  sure that  different  kinds if toroids will require  different numberes of wraps for the primary

Both   the primarys  and  secondarys of all the coils  are connected the same .....end of one wire with the start of the other .......traditional JT style.

The  coil  with  6 toroids  produces  75 V  with no load ...... 37 V driving  my 90 LED array .....the  array was bright but not full power.

The  coil with 4 toroids produced  31 V unloaded   30 V loaded .......the array  was much dimmer

The coil with 2 toroids  produced  37 V unloaded   31 V loaded ..... the  array was  lit b ut  just barely .

The  voltage seems to be set by the number of wraps  on the  coils.
The power level  seems to be a set by the number of torids
If  you   try your circuit and do not have enough power........just add a few more toroids.
It looks to me that all the toroids  in a particular  coil should be wrapped  with the same number of wraps....... It seems better to  use one coil less  if  wire runs out .......rather than having a toroid with less windings.........the odd toroid  seems to drag  the whole thing down.

gary

[resonanceman]

This  is a coil with 8 wraps each toroid ( #20 bell wire )

Same configuration  as above.

This  coil  produces  19 V loaded .
21 V unloaded.

[resonanceman]

Lets see what can  be done  with this system

Below is a picture of an  unknown  toroid.
It is  from  a power supply .
The  toroid is probably  iron powder or something.
It  it takes  quite a bit to get it  going.

The second picture is  the same coil  with  the  8 wrap  coil
The  output  of the  8 wrap is the same as before.
The  output of the  unknown  coil  is 11 V foir the small winding 23 V for the larger winding.
The  larger winding is  clearly  not putting out as much as it should........underdriven .

gary

[resonanceman]

I added  2  5 for $1 toroids  to the  unknown  coil by putting candy cane  windings over the  empty spots on the coil.

I  used 3 wraps each toroid  with brown wire and  2 wraps each toroid with blue  wire.

The intention is to couple  the 3 toroids  to catch more magnetic flux from the  primary

gary


Edit

it turns  out that this  did  not work out...... I am pretty sure it can be done.......but  havn't got it to work yet

[jeanna]

What happened?
but first start another thread so this stays 101

what happened?

jeanna