Joule Thief

[Pirate88179]

What's the point? Why would anybody interested in OU want to buy it?

Omni:

Maybe I can answer that one.  Perhaps it is because you can't seem to buy one on the open market as of now.  For example, I have had many requests to build JT powered led flashlights that operate on a single "dead" AA battery and run the leds brighter and longer than they do on the 4 AA's that come from the factory.  I have already done this for free for a few friends.  Why?  Because you can't buy one.  This puzzles me because if I were a design engineer for a flashlight company, I would make this and put it on the market.  Why do they not do this?

It is not, of course, OU but still it is a leap ahead for what technology is commercially available.  What are your thoughts on this?

Bill

[Omnibus]

@Pirate88179,

For those purposes, yes, I do agree. Moreover, I've always felt that a real OU research should be don on this JT. So far, I'm not aware of quality energy balance being measured on it. I'd be willing to do such measurements (probably in January because I've some other things to take care of at present) but, like you said, it cannot be purchased anywhere and I don't want to rediscover the wheel by making one myself.

[conradelektro]

Why one does not find a Joule Thief circuit on the market:

My experiments with Joule Thief type circuits and CFLs (compact fluorescent lamp) showed, that when measured carefully, a brightly lit CFL used more energy with a Joule Thief than with a conventional circuit (the circuit which is present in CFLs bought at a store).

One can light a CFL with a Joule Thief with comparatively little energy, but then the light output is marginal. It looks good when filmed in a dark room, but the room stays very dim.

This is also true for LEDs. One has to measure the light output of the LEDs with a lux-meter in order to see how dimly they are lit with a Joule Thief in comparison to the situation when the specified amount of energy is put through them.

Still, the Joule Thief circuit is useful for LEDs in cases where one does not need very bright LEDs (which are too hard on the eyes), e.g. for a night lamp or an indicator light.

The commercially available LED flash lights put too much energy through the LEDs, one does not need such brightness in practice. Adding a Joule Thief (and using only one battery instead of four) reduces the brightness (which is then still good enough) and of course the power consumption.

The Joule Thief is interesting and educational, but I did not see any over unity. A person who thinks that his Joule Thief is over unity should by a lux meter http://en.wikipedia.org/wiki/Lux  http://www.maplin.co.uk/Module.aspx?ModuleNo=46557 .

Greetings, Conrad

[crowclaw]

Omni:

Maybe I can answer that one.  Perhaps it is because you can't seem to buy one on the open market as of now.  For example, I have had many requests to build JT powered led flashlights that operate on a single "dead" AA battery and run the leds brighter and longer than they do on the 4 AA's that come from the factory.  I have already done this for free for a few friends.  Why?  Because you can't buy one.  This puzzles me because if I were a design engineer for a flashlight company, I would make this and put it on the market.  Why do they not do this?

It is not, of course, OU but still it is a leap ahead for what technology is commercially available.  What are your thoughts on this?

Bill

Hi Bill, and Happy Xmas to you. There are LED flashlights available  of course using  JT circuits to drive several LED's the difference being that they are optimised to provide maximum performance around their source voltages...
1.5 volt upwards, much below and they begin to fail. The batteries are disposed of and replacements are purchased!! Now the thing is_ any attempt to squeeze any more power out of these "exhausted" cells will affect sales Bill   tut... tut. Hm mm... so lets think about this!! need to configure the circuit in such away that it can be tuned into resonance below 1.5volts or whatever makes up the supply source voltage. As usual any improvements will come at a price of course, and one has to convince the buyers that Torch "A" lights a lot longer than Torch"B" but costs more to purchase. The only other saving grace of course is the WIND UP flashlight which incorporates several technologies... a generator, LED's, and super cap's. We all new that  a DC model motor produced a DC voltage by turning it's shaft. It took Trevor Bayliss to develop the idea further, Oh well never mind. May be there is a bright... get it! bright future for the JT circuit yet. Sorry to go on a bit here, you made a good point Bill. Merv

[Omnibus]

@Pirate88179,

If you think there's a market for it why don't you take up on it? In this way you'll be able to finance your more important projects in the OU field. It's true that the battery producers won't like it, as our friend says, but so what. There are always secondary markets, there's internet. This is a nifty little gadget many would go for. What do you think?