Single AA battery to light WHITE LED for long-long time

[Koen1]

where did that "target battery" come from all of a sudden??

There is no "target battery" in the schematic you posted, nor do I see any in the pics you posted...

What you had was a smartly switched LED driver running off a battery,
but what you describe in this last post sounds like a bedini battery charger
("back-popper") circuit, where your dead battery gets recharged by the
other one...

please explain?

[renaud67]

Hello,
look at that :
http://www.elektor-electronics.co.uk/magazines/2007/september/pr4401-led-driver.227959.lynkx

[innovation_station]

 

NICE LINK

but im sure it can get much better lol

ist

[renaud67]

NICE LINK

but im sure it can get much better lol

ist

no doubt 

[Koen1]

Hello,
look at that :
http://www.elektor-electronics.co.uk/magazines/2007/september/pr4401-led-driver.227959.lynkx

Hey thanks for that link Renaud!

So, it seems the trick is fast switching again..?
Well, interesting little circuit...
I am still a little bit puzzled as to how exactly 1.5V at extremely low milliamperage
(with a dead battery usually around the 0,001 to 0,01 mA) could light a LED
(LEDs usually need a couple of hundred milliamps at a couple of volts).
After all, even if you have a circuit that works the voltage up from 1,5V to
the voltage needed to run the LED, and let's use a very positive estimate of 3V for
discussion purposed, then the milliamperage delivered by the battery should
theoretically result in an even lower amperage, according to standard transformer
theory. And LEDs don't just emit light on voltage alone. They need the amperage
too.
Now it may be that the LED is in fact pulsed at the right voltage and amperage
at a high frequency, faster than the human eye can see, and this looks like
the LED burns continually...
But then still, it seems quite a neat trick to run a white LED off a dead AA battery...

Anyone for some more constructive insights?