Joule Thief

[timmy1729]

http://www.youtube.com/watch?v=XLNItTf9NrM&feature=channel_page

@ All:

Have a look at the above video.  This fellow says that we can double the amount of back emf by using a few tricks.  This may well apply to our research here.  Check out his other videos as well because he explains how this works.  See what you think and let me know.  Thanks.  http://www.youtube.com/watch?v=zP4dfxXhxxg&feature=channel  This video, he charges 4 batteries with only 2 batteries.

Bill

Can anyone tell me what kind of motor he is using in the video?

[timmy1729]

@Timmy: yes, those yellow things and the green one too are transformers.
Not sure how you hooked up your meter there, but if you fed a steady DC
into them it may well be that you didn't measure much on the output side,
as typically induction in trafos happens when the current builds or drops
and when the magnetic field builds up or collapses, but not really when a
steady current maintains a magnetic field. Generally trafos work with pulses
or alternating currents. I may be telling you stuff you already know and if so
then forget about what I said just now, I'm not trying to act smart, I'm just
trying to think along with you there on why you didn't get a reading on the secondary.

By the way, I see a couple of really nice looking ring cores there too,
should be usefull in winding your own JT coils if you're going for that

@slayer: thanks for pointing out that suggested bemf connection.
So, if I'm folowing you, you're just saying connect the positive bemf feed to either the circuit positive or the battery negative,
and connect the negative bemf feed to either the circuit negative or the battery positive
And again, not to be a smartass, but doesn't a rectifier consist of diodes?

regards,
Koen

@Koen
So, what power source should I use to try this out? I've got AA and D batteries. He only used a battery in his first video. Should I try hooking wires to the collector and emitter on my JT and then hooking them to the transformer? So, really, what should I use to try this?

Oh, when giving an answer; when in doubt, Timmy does NOT know it 

[Koen1]

Well if you mean you want to test the transformers,
you could produce pulses crudely by connecting only
one of the wires from the battery to the trafo primary,
and tapping the other primary wire to the battery terminal...
That should create a little pulse of DC every time you
tap the wire on the battery, and every pulse should
be transformed into output on the secondary. That way
you can check what volts (and amps) the output is
with your given input.
Of course this depends on the ratio of the transformer
(primary vs secondary that is), and this plus the wire
resistance determines the minimum DC voltage feed.
I would say first do this with your weakest battery, see what
readings you get, if this is not clear enough then take a
larger battery.
Seeing how one can easily produce several hundred volts using a
small transformer and an AA battery, I would rather be safe than
sorry, and use the weakest battery first. Unless you really don't
mind getting a couple of hundred volts jolt your fingers, then
I'd say use any battery you've got.

I'm not sure what exactly you're planning here... I thought you just wanted
to see what the transformer ratio was, in other words, what the output
of the trafo is at a given input.
But now it seems you want to use your JT as power source and feed the
transformer from that?
Well I suppose that may work so I'd say try it
I'm not sure, I think there may be a matter of the trafo interacting with the
JT core or some resonant effects that may influence the function, but
to be honest I think guys like Gadgetmall, MK1, Sparks, Slayer, etc can
tell us more about that than I can tell you.

regards,
Koen

[slayer007]

@Koen
So, what power source should I use to try this out? I've got AA and D batteries. He only used a battery in his first video. Should I try hooking wires to the collector and emitter on my JT and then hooking them to the transformer? So, really, what should I use to try this?

Oh, when giving an answer; when in doubt, Timmy does NOT know it 

Just a couple post I posted how I was getting twice the voltage comming off the emittor and collector of the 3055 on my JT.
By using a rectifier instead od a diode.
Mabe the recitier is picking up the voltage both way. Any ideas

[timmy1729]

Well if you mean you want to test the transformers,
you could produce pulses crudely by connecting only
one of the wires from the battery to the trafo primary,
and tapping the other primary wire to the battery terminal...
That should create a little pulse of DC every time you
tap the wire on the battery, and every pulse should
be transformed into output on the secondary. That way
you can check what volts (and amps) the output is
with your given input.
Of course this depends on the ratio of the transformer
(primary vs secondary that is), and this plus the wire
resistance determines the minimum DC voltage feed.
I would say first do this with your weakest battery, see what
readings you get, if this is not clear enough then take a
larger battery.
Seeing how one can easily produce several hundred volts using a
small transformer and an AA battery, I would rather be safe than
sorry, and use the weakest battery first. Unless you really don't
mind getting a couple of hundred volts jolt your fingers, then
I'd say use any battery you've got.

I'm not sure what exactly you're planning here... I thought you just wanted
to see what the transformer ratio was, in other words, what the output
of the trafo is at a given input.
But now it seems you want to use your JT as power source and feed the
transformer from that?
Well I suppose that may work so I'd say try it
I'm not sure, I think there may be a matter of the trafo interacting with the
JT core or some resonant effects that may influence the function, but
to be honest I think guys like Gadgetmall, MK1, Sparks, Slayer, etc can
tell us more about that than I can tell you.

regards,
Koen

No, I was simply asking how to get enough juice through the transformer so I can use my meter. The JT was just a wild idea meant to show my confusion    I wasn't serious, but I will try it since Slayer got more voltage from doing that. I was thinking that the transistor creates pulses. I don't know if that is me misunderstanding what is going on or not.

Does anyone have any idea what motor he was using in his other two videos? If it is in something I have at home I will use that. If not, I am going shopping later anyway.