Nuclear battery

And more importantly, less wasted power. The switching supply can supply the few microamps as a finder current, too. Low-Iq switchers are all about, these days. If one doesn't like that idea, a large resistor to supply the leakage, still works.

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That's not what you wrote about. If you analyze the actual efficiency of s uch circuits you will find the losses in a switcher are not much less than the losses in a linear running from 4.5 volts. Most LED lights uses 4.5 vo lts. I don't think the choice of going with a single 1.5 volt cell or 3 ce lls is an issue of "cheapies". It's just a design decision and the 3 cell units hold up longer because of the higher energy in three cells compared t o one. Unless size/weight were an important factor, I'd go with the 3 cell solution.

Yep, a large resistor around the current regulator and switch. No point in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better a s the battery voltage drops. By the time the voltage gets too low to work some 80 or 90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck, someone inve nted a very thin bracket to put around a AA battery to do the joule thief t hing and it has a significant cost. My LED light only cost $10 and works g reat. Add a switcher and it would be $15.

Utter nonsense.

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in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets bette r as the battery voltage drops. By the time the voltage gets too low to wo rk some 80 or 90% of the battery is used up.

nvented a very thin bracket to put around a AA battery to do the joule thie f thing and it has a significant cost. My LED light only cost $10 and work s great. Add a switcher and it would be $15.

Yes, using a switcher to get 10% better efficiency from a $0.25 battery is exactly that, utter nonsense.

$5? Bullshit. You're completely full of shit, in fact.

I don't think they care so much about the linear wasted power but the switched mode current source trick made single AA battery LED torches possible for under $5. They even do flashing modes as well.

The big advantage is that the thing runs at almost constant brightness right up until the battery is really on its last legs. This can be a disadvantage I have had more than one Duracell corrode on me recently. Other cheaper brands do not seem to fail so annoyingly. I don't know if they are clever forgeries or what but I have stopped using them.

There are chips that can do it for next to nothing and have been for some while. I recall a low power sample device being a give away on the front of a popular electronics magazine back in the early 2000's.

in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better as the battery voltage drops. By the time the voltage gets too low to wor k some 80 or 90% of the battery is used up.

vented a very thin bracket to put around a AA battery to do the joule thief thing and it has a significant cost. My LED light only cost $10 and works great. Add a switcher and it would be $15.

The fact that something is given away doesn't make it cheap. Tesla "gave" me free Supercharging worth $30,000 or more.

The chip is about the same cost as the inductor. The point is it provides virtually no benefit (personally I see the blinking mode as a liability) if the buyer doesn't know it's there.

Sans the inductor a simple current source chip or circuit (how many transistors? 2, 1?) Is cheaper and very effective.

But you get good power efficiency from red, and green is the peak for NIGHT vision, which means one is light-blind the moment you switch it off. Red light doesn't desensitize the low-light (rod) cells, so a red illuminator doesn't leave you blind in the moonlight afterward.

An old-fashioned solution is a neon lamp in a light switch (I'm using one for the garage, and another for the hallway), and the newer one is an outlet-plate that steals AC for low-level lighting

but neither does much for the 'find my flashlight' problem when power is out.

for the

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out.

I bought a couple of LED recessed fixtures and a couple of dimmer switches that the LED figure recommended for compatibility. The dimmers had a light (likely a neon bulb) across the switch. The LEDs act as a nightlight beca use of the current through the neon bulbs. lol The dimmer switches contro l the LED erratically and the initial half of the dimmer switch movement do es nothing.

I'd hate to see how badly a non-recommended dimmer would work.

Scotopic vision at night peaks at around 510nm in the green which is the rods peak sensitivity. That rod pigment is unaffected by red light beyond 600nm so you can afford to use that without losing night vision. Submarines and observatory control rooms used to be lit that way and many still are. There has been a recent switch to very dim white light.

Moonlight is *way* more than you need. The red light requirement is so that you can still see the very faintest stars without having to wait half an hour for the pigment to recover. Another interesting trick is to breathe pure oxygen which boosts the eyes sensitivity (especially when at high altitude which most professional observatories are).

It is easy enough to make a red LED torch. It was pretty much the first thing amateur astronomers did when the first red LEDs became available. True long wave glass filters were expensive luxuries back then.

Interestingly though now when reading charts very dim white light pointed downwards is preferred since many people find long wavelength red light very hard to read by. Provided you keep it diffuse it doesn't affect your night vision any more than looking at the milky way does.

With enough 1950s radium watch-hands, *anything* is possible.

I've noted some fluorescent lights will glow for hours after removing power. Or was that caused by the radar from the airport tower 4500 ft from my bedroom when I was 13 yrs old. At least that was a thought I had then.

Mikek

An airport radar sweeps, so would make a flash of light every second or two.