Joule Thief

[Yucca]

Hello all JTers,

I recently made a flyback transformer based HV supply. It is configured like a JT using one of the flyback low V coils as a trigger coil.

It has an input power range from about 1.5mW to about 12W.

here's a vid of high power operation:
http://www.youtube.com/watch?v=qMl3pXvJ-mY&feature=channel

Today I experimented with it's low power operation a little. Pics below are of a neon bulb and LED lighting at 1.5mW (1.5V 1mA). I think it could be made even more efficient using zener diode for base bias instead of the potential divider resistors at present which constantly burn a little power.

So if any of you see a trashed TV, maybe take it home, strip it for parts, then take it to the dump.

NOTE:
the little toroid on the board in the pic is not a JT it is just a filtering choke for the low voltage input line. The TV flyback is operating like a normal JT but with a third high turn winding for HV out.

@Jesus,
Grab yourself a working flyback as soon as you can, you'll really like it. at my local council refuse site, if you ask the workers nicely and tell them you wan't a spare part out of the TV then you'll return it, then they just let you take a TV away no problem.

[nievesoliveras]

@ nievesoliveras

Nice looking spark gap. Are you duplicating what Yucca did?

Yes. And also trying to learn at the same time.
I also got a yellow transformer to duplicate @resonanceman's.
But mine has 8 legs one side and 4 legs at the other side. It is not equal.

Jesus

[nievesoliveras]

Hello all JTers,

I recently made a flyback transformer based HV supply. It is configured like a JT using one of the flyback low V coils as a trigger coil.

It has an input power range from about 1.5mW to about 12W.

here's a vid of high power operation:
http://www.youtube.com/watch?v=qMl3pXvJ-mY&feature=channel

Today I experimented with it's low power operation a little. Pics below are of a neon bulb and LED lighting at 1.5mW (1.5V 1mA). I think it could be made even more efficient using zener diode for base bias instead of the potential divider resistors at present which constantly burn a little power.

So if any of you see a trashed TV, maybe take it home, strip it for parts, then take it to the dump.

NOTE:
the little toroid on the board in the pic is not a JT it is just a filtering choke for the low voltage input line. The TV flyback is operating like a JT.

@Jesus,
Grab yourself a working flyback as soon as you can, you'll really like it. at my local council refuse site, if you ask the workers nicely and tell them you wan't a spare part out of the TV then you'll return it, then they just let you take a TV away no problem.

Nice work!!!
If the ladder is working with the 1.5v also. You are great!!!
Does it need a new schematic for the connections?

Jesus

[Yucca]

The ladder only kicks in at higher powers, it would be great at the lower power though!

I just realised that the zener for greater efficiency would not be needed for low power operation, best would be to remove the resistor divider completely and then just put 100ohm between trigger coil and base.

[xee2]

@ Yucca

Today I experimented with it's low power operation a little. Pics below are of a neon bulb and LED lighting at 1.5mW (1.5V 1mA).

Thanks for the report. I would think you must have had to changed your 100 ohm resistor to a 10 ohm resistor in order to get the transistor to turn on with 1.5 volts. In fact, I would suspect that it would work with only the 1000 ohm resistor when using 1.5 volts.

EDIT: I see you were posting the same idea while I was posting this.

EDIT 2: I think I was wrong about the 10 ohm resistor. You would need a larger value, not a smaller value to replace the 100 ohm resistor.