nightlite circuit needed

I'm looking to build a nightlite..6 volt supply..driving a white Nichia at low level. We have a very dark hallway..am using a tap light with a green hybrid ceramic led array in it...nice, but it sucks down my NiMh's too quickly. I need efficiency more than anything else. Anyone got a simple schematic?

try the joule thief but do not use the nimh because it will overdrain them, just use cheap or used batteries. They run for more than 48hs from bright to dim.

Pablo

Thanks..I've used that circuit before...however, I'd like to use 6 volts in and get better run time..I don't need alot of illumination..just really a glow to see the stairs in the dark. Anyone else?

Why don't you use dorcy coolblue flashlight(4AA) or that LED bulb? To my surprise, it glows more than 200hrs and it is brighter than single Nichia LED. I think that is the most easy way for that purpose.

The LM334 based 'nightlights' I've got spread around the house (five at present) are in two groups, those that run 'full time' get a month on 1700 mAh NiHM (three cells only, although four would work with lower efficiency), those with photocells (two of 'em) get twice that per charge.

The drive a bit under 2 mA ('low' setting), plenty for the task at hand.

On 'medium', it's a week, on 'high' (a bit under Ultra level) 'only' two days. Or four with the photocell trick.

Doug Owen

LM334 based lights? A month would be good! The tap light is only on for about 8hrs a night. We turn the light on when we go to bed ..then turn it off when we get up. I could put a dummy cell in and run it on 3 AA's. What is this LM334 circuit you speak of?

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unclearty said:
LM334 based lights? A month would be good! The tap light is only on for about 8hrs a night. We turn the light on when we go to bed ..then turn it off when we get up. I could put a dummy cell in and run it on 3 AA's. What is this LM334 circuit you speak of?

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I really got to get this stuff up on a web page sometime....

The circuit I typically use can be found on the National data sheet , on page 8 on the right, labeled 'higer output current'. I typcially build them with several switch selected shunt resistors (47 ohms for low), and use 2N3906 (higher gain version of the 05). Fine up to a hundred or so mA. The LED goes in series with the collector, typically. With 3 cells you can regulate down under .1 Volt difference between Vbatt and Vf. At the sort of currents we're talking about (under 10 mA) you should be able to use a more modest circuit, say the 'basic 2 terminal current source' next to it (although the voltage requirement is a bit higher). The LED goes in series (above or below) that circuit.

How's your soldering?

Send me a PM, let's see if we can work someting out.....

Doug Owen