Joule Thief

[Pirate88179]

@ All:

I just found this over at Electronics Goldmine:

http://www.goldmine-elec-products.com/prodinfo.asp?number=G16329

It is a camera board that is on special for $.79 ea.  It is too bad we can't see the reverse side of this thing in a photo BUT it says this board was designed to operate on 2 AA batteries...yes that is 3 volts!!!

It might be worth getting a few of these to see if the transformer is even larger than our Fuji and possibly the transistor can handle the additional voltage as well?  Maybe we could even figure out the tracings and modify it similar to the Fuji.  There are some smart guys here that could do that I am sure.

I am just very curious about it being set-up to run on 3 volts...never saw anything like this in any camera I have taken apart.

Bill

***EDIT***

PS  I suppose it could be set-up to run on 1.5 volts and they just used the batteries in parallel for a longer run time but, I don't know why they would need to do this unless it has like an auto wind type feature.

[xee2]

I corrected the circuit problem in my replication attemp and the efficiency is now only 36%, but this is still a bit better than a normal Joule thief. My new video is at:
http://www.youtube.com/watch?v=smOiVmKv9f8

[electricme]

Bill:

Very nice find there, as you say pity we can't look at the component side of this board. I will go and take a look see at it shortly


I was thinking how to make the CFL brighter, and I think I have found a way, well in my mind that is.
A couple of years ago I was fiddling around with MOTs and came across a web site where a few chaps had managed to double and quadrupole the Hi Voltage out and were doing all sorts of crazy things.

In reality there is no difference electrically in principle between a MOT or the tiny hi voltage transformer on the camera boards, I can see no problems in trying to marry up two tiny hi voltage transformers to double the output and give a much brighter CFL light.

The primary windings are simply connected in parallel, the secondary output of each transformer are connected in series. We need to find the start and end windings on the secondary and connect the ends in such a way to double the output. In the circuit I have drawn below you can see how to connect 2 HV transformers to each other.

As I haven't ever measured or compaired the tiny Hi Volt transformers on a photo flash board I don't know if the circuit is the same, maybe some one can do a resistance coil test and let me know.
You would need to unsolder a Hi Voltage coil to do this, so you can tell which other end of the Hi Volt coil wire goes to which pin that is soldered to the PCB.
Knowing this will let you know how to connect the secondary coils together.

The upside is, once we have a working double Hi Volt setup we could triple or even quadrupole the output, hey maybe burn out a tube ha ha.
The downside is, we use more power, but by changing the AA battery for a C size battery we can still get the same run time (or more) as the AA battery.

Jim

[Pirate88179]

Jim:

Great idea on the transformer adding.

A word about cfl's...in my opinion, based upon my own experience and experiments, I will no longer work with tubes or cfls again.  Besides the mercury issue, in my latest video as I post a few posts back, I do a comparison between the light from a cfl, and the light from my single LOA light and also a double LOA light.  These use much less power (I will try to get some readings after work tonight) but, as seen in that video, the light from the single LOA led bulb is twice, if not more, than that of the cfl.  The double LOA light is much brighter still...all on a single AA.

I realize that not all areas of the world will have access to these new bulbs...at least maybe not for a while.  This is just a choice that I am making.  I know that Jeanna experimented with these bulbs long ago and it has only been recently that I have decided to play with them.

They put out an incredible amount of light and look much brighter in real life than on my videos.

We could still use your idea about ganging the transfos and see just how much one of these lights will take...ha ha.  We won't know until we try.

Bill

[resonanceman]

Bill:

Very nice find there, as you say pity we can't look at the component side of this board. I will go and take a look see at it shortly


I was thinking how to make the CFL brighter, and I think I have found a way, well in my mind that is.
A couple of years ago I was fiddling around with MOTs and came across a web site where a few chaps had managed to double and quadrupole the Hi Voltage out and were doing all sorts of crazy things.

In reality there is no difference electrically in principle between a MOT or the tiny hi voltage transformer on the camera boards, I can see no problems in trying to marry up two tiny hi voltage transformers to double the output and give a much brighter CFL light.

The primary windings are simply connected in parallel, the secondary output of each transformer are connected in series. We need to find the start and end windings on the secondary and connect the ends in such a way to double the output. In the circuit I have drawn below you can see how to connect 2 HV transformers to each other.

As I haven't ever measured or compaired the tiny Hi Volt transformers on a photo flash board I don't know if the circuit is the same, maybe some one can do a resistance coil test and let me know.
You would need to unsolder a Hi Voltage coil to do this, so you can tell which other end of the Hi Volt coil wire goes to which pin that is soldered to the PCB.
Knowing this will let you know how to connect the secondary coils together.

The upside is, once we have a working double Hi Volt setup we could triple or even quadrupole the output, hey maybe burn out a tube ha ha.
The downside is, we use more power, but by changing the AA battery for a C size battery we can still get the same run time (or more) as the AA battery.

Jim

Jim

I have never tried putting the primarys in parallel before.
If you put the primarys in series you will have a candy cane coil made with transformers rather than toroids.

I plan on playing with the same kind of idea  tomorow.
I have a couple of camera circuits that are AA but only 4 connections on the transformer.
I also have a fuji AA that has 5 connections on the transformer.  If the 5th connection is a center tap for the primary making a JT with that one will be a snap.


Getting back to the candy cane thing.
If you put  your primarys and secondarys both in series  it works for the most part like  one big inductor  with the an  equivalent number  of wraps

I do think  you will be happy with what  you find .......there are lots of possible combinations with candy cane  coils........ one is to put  string of primarys in series then  try to light a CFL with each secondary

I look forward to seeing your results


gary