cold cathode

[bluepilgrim]

I don't find too much about cold cathode lights yet, but I think I like them.

I found this http://meridianelectricco.com/product_ID.asp?ID=49 (CCFT & LED, 4 AAA) at the local dollar store the other day -- closeout apparantly, and picked up half a dozen of them. Cheap plastic case and not very bright, but still enough as an area light to navigate in a dark room, and the led is like a cheap keychin light -- and only a dollar! (Since I'm poor I look for cheapest stuff available.) But it drained the dry cells even when off. The battery tray is coated with a metal film -- I think as a radio interference shield -- which touches the spring contacts, resulting in about 80 ohms across the dry cells. I took it apart (again -- I already had it apart to see what was in it) and just wrapped a little piece of plastic sheeting (from a food bag) around the bottom of the spring. I guess the right engineer didn;t know what the left engineer was doing?

Anyway, I like the thing -- it was only a dollar. You might find some of these around if they are dumping them, and it's just two screws and a two minutes to fix the problem.

I will be looking at cold cathode lights, as well as LEDs, when I'm window shopping now -- and am waiting for more of these to hit the market. I'm old enough (pre-transistor) that both types seem like a kind of magic to me -- like my pocket calculators do.

 

[importculture]

I know you wrote that you liked cheaper lights but I love my energizer cold cathode and nichia led lights. They take 4AA's and are very energy efficent. If it sounds like something you'd like you should check it out online. I don't remember how much they were, definately not a dollor but alot cheaper than most any other lights we buy here on cpf.

 

[bluepilgrim]

On line prices are listed at about $15 to $30.

I've been reading up on the power supplies (not yet significantly understood or digested -- this is complex circuitry) -- http://powerelectronics.com/spotlight/buck_converter/ has a fair bit, as well as http://www.deltartp.com/dpel/dpelconferencepapers/APEC94 LCC inverter lamp driver.pdf and the wikipedia entries, starting at http://en.wikipedia.org/wiki/Buck-boost_converter

I haven't found any data sheets on the tubes, or even where they can bought as 'components' -- and they are all straight.

There are kits available for computer case lighting, but I also see than many of these converters self-immolate and can take a computer with them.

Cold cathode lights get very technical very quickly, so it looks like rolling your own or doing a mod is rather challenging, and there aren't many store-bought ones to choose from yet -- especially in portable flashlight form.

I am in the process of making an adapter to run one of the little ones I got on a 6v lead acid battery (or a few D cells) from a Power Wheels kid's go cart. That should keep it going all night even at the North Pole in the winter.

I looked at some of the house current light bulbs available, and there aren't many of those either, and are expensive. I do see they are used in autos, and in backlighting for laptops, but cold cathode looks more like mostly for specialized lights and the future yet. If you could get the power supply to run it those bulbs could make a very nice camping or blackout lantern (you could use a standard 12 volt to 120 volt auto cigarette lighter inverter), if you didn't need something to fit in your pocket -- but that's no worse than the old gasoline coleman lamps.