What has happened to the CRT?

Was that inerent in the flat screen technology, or because of the lack of a larger color pallete available in the driving circuitry? Not that it matters for now, but maybe in a few years things can be better. Worst case, resuming each pixel can respond fast enough, you can PWM it to make it give a wide range of brightnesses.

With MP3 audio and similar psychoacoustic compression formats broadcasters use (I've sometimes heard syndicated radio show "Handel on the law" that sounded horribly wishy-washy because of the low bitrate), and digital TV, the quality is definitely going down. I can see the next Star Trek series (if there IS a next, it looks unlikely): "To boldly bring you artifacts no man has ever seen or heard before!"

Hello Ben,

Not really but they look less obtrusive in the kitchen. The clock radios we have are all LED. Gas discharge does get cheaper when you have to display much more information than a few numbers. You can have them customized almost like LCD, with your company's logo and all.

Regards, Joerg

I'm sure Ben doesn't mean gas discharge btw. Probably he means vacuum flourescent display ?

Graham

I've used them and rather like them. Try and get any other inexpensive 16 char 1 line alphanumeric display that has high visibility.

The heaters take a good bit of power btw.

Graham

Low power? There are filaments in these displays!

And b.tw. most microwaves I have seen have LCD's.

Meindert

Those VFD displays are very nice. I built a clock out of one I got someplace, and it is very bright and visible, even in direct sunlight. Requires a 1.8 VAC filament supply, and a 25VDC driver for the display elements.

I ripped apart an old VCR a few years ago, and it had one as well. The old VCR used a linear power supply, and had windings for both of the VFD voltages, as well as the winding for the motors and such.

Hello Graham,

Yes, I guess he did. I like VFDs much better than LED or LCD.

Regards, Joerg

Hello Chris,

Ours was $59 and it doesn't ;-)

Regards, Joerg

Hello Ben,

That could be a challenge as addressing this many pixels is kind of tough already.

But so is the quality of the programming content. Seems there is a proportional relationship.

I can imagine the day when our TV croaks and we don't bother to buy a new one. It actually happened after an international move. The old TV wouldn't have worked anyway because of a different standard. But we didn't notice because we never plugged it in for eight months. Then a winter storm approached and we wanted to see a weather forecast. Plugged it in. Duh! Blushed a bit 'cause an engineer shoulda known, then quietly bought a new set.

Regards, Joerg

I suspect he means vacuum fluorescent, unless it's out of phase by pi.

The numbers on my microwave are pale greenish, almost cyan, but flat as an LED or LCD - Damn, now I have to go and look... It looks for all the world like green LEDs, but I have no idea how they'd do the little peripheral word thingies ("COOK" "DEF" "CLOCK", that sort of thing.).

Cheers! Rich

Hello Rich,

That's in all likelyhood a VFD. Take a magnifier and peek at it: Most likely you see structures that look like traces. Just as you'd find them on LCD.

Regards, Joerg

No. they are vacuum fluorescent. much better lifetime and cheaper than gas discharge and more customizable than LED. better visibility than LCD.

And, in a way, couldn't you say that they're sort of a multiple-section CRT? After all, the phosphor does get lit up by cathode rays, right? ;-)

So, anyway, ever since I heard that college boys use "conventional current", which flows from positive to negative, I've wondered how do the positrons know exactly which pixel to leap off of, wend their way through posistatic decelerators and magnetic inflection coils, and end up exactly at the cathode? ;-)

Thanks! Rich

radios

gas

current",

I'm not going open that well-cooked can of worms agains, but I offer two factoids.

1. The arrows in semi-conductor symbols point in the direction of conventional current flow.
2. I have some US Navy training materials dating from the earliest days of semiconductors (pre-1950). They adopted the OPPOSITE convention; they used the familiar semiconductor symbol for the diode, but the arrow pointed in the direction of electron flow, not conventional current flow! Probably easier for the vacuum tube guys to learn, which agrees with your point. I don't know when the Navy decided to use the industry standard symbols.

Oh, yeah, us techie-types learned that early on. Since it's semiconductors, we can get away with just saying it indicates the direction of hole flow. :-)

Well, I never saw anything dating back that far (I was born in 1949), but I remember when they announced the transistor, and sometime in that sort of timeframe (mid-1950s), my Dad brought home a couple of textbooks that explained transistor physics in terms that a footsoldier could understand. It had perspective drawings of the lump of silicon with holes jumping from atom to atom, and stuff. I remember a very dramatic illustration of how the base current can have such a huge influence on the collector current.

Thanks! Rich