Dan's Data letters #10Publication date: 12-Nov-2002.
Last modified 03-Dec-2011.
I've been modding cases for a bit (your page on the LED array was very useful) and I intend to build a case out of Perspex. One of the issues that I have with that is the shielding. I know not all cases are built out of solid metal these days, but a case built entirely out of Perspex would have no intervening metallic shield between the mainboard and the user.
Approximately how much radiation will escape from an unshielded case, and at what distance would you be safe?
That also brings into mind the trend in big side windows in cases, how much radiation are they letting through?
PC system units have no hazardous emissions. You could sit on a bare PC motherboard and not be exposed to any dangerous radiation. Gluteal lacerations from the components and grievous bodily harm from the owner of the gear you just squished, yes, but no radiation hazard.
PC system units do emit some radio frequency energy; with no case, or a plastic one, all of that will get out and mess up nearby TV and radio reception to some extent. This may, technically, violate one or another law where you live, but if you're not bothering the neighbours with it, you needn't worry about it. If you're selling computers that don't meet RF emissions standards, then you may find yourself severely busted. Just using one, though, isn't a big deal.
Getting back to the danger issue, PC system units are safe because they emit no measurable ionising radiation. CRT monitors emit a small amount of ionising radiation, but it's really small compared with everyday natural sources (see this IBM page, for instance, which has an atrociously bad graph but is telling the truth otherwise).
As far as non-ionising radiation (radio frequency and lower, in the case of computers) goes, there's some evidence that such radiation can affect biological processes in ways beyond what you'd expect from simple heating (which, classically, is all it's meant to be able to do), but the laboratory and epidemiological evidence to suggest that low level non-ionising radiation poses any real health risk is sparse. Not nonexistent, but not nearly persuasive enough to justify mass hysteria about mobile phone emissions causing brain cancer and so on.
The "standard" resolutions for 4:3 computer displays (640x480, 800x600, 1024x768, 1280x1024, 1600x1200) are all 4:3 aspect ratio, except for 1280x1024. For that reason I run my display at 1280x960. But many LCD screens have 1280x1024 native resolution, with a 4:3 viewable area - does that mean the pixels aren't square?
What the heck is up with that? And why doesn't that bother anyone but me? Why isn't the standard 1280x960?
You're right. 4:3 screens running at 1280 by 1024 do not have square pixels, and as a result do not generally draw things quite the right shape.
LCD screens with 1280 by 1024 resolution, though, aren't actually 4:3. They're all 5:4, as far as I know; a 17 inch 1280 by 1024 LCD will probably have a roughly 338 by 270mm viewable area. As a result, their pixels are still square.
Pixels on CRTs can have any shape, within reason, because they just fall where the video adapter tells the monitor to draw the lines. There is no hardware-set resolution on a CRT, beyond the limits of its screen-painting electronics.
LCDs have a hardware pixel array, onto which other resolutions map poorly, if at all; a 1280 by 1024 LCD that had a 4:3 aspect ratio would genuinely have rectangular pixels, and still have them even if you displayed some lower resolution on it. The (probably square) pixels of lower resolutions are just mapped fuzzily (or, for older LCDs, blockily) onto the physical pixels of the LCD.
The difference between 5:4 (1280:1024) resolution aspect ratio and 4:3 means that things that're meant to be round or square will be oval or rectangular instead, if you're using that resolution on a 4:3 screen and the software you're using isn't aware of the screen dimensions and rescaling the image to suit. Which it probably isn't.
The difference, though, is actually quite slight. When you realise that 5:4 and 4:3 can also be expressed as 20:16 and 20:15, you can see that we're not talking about a large distortion, here.
Just a quick question about those M4 speakers you reviewed recently. Am I correct in assuming that these speakers would not work unassisted with a standard sound card? (I've got a Sound Blaster Live of some description.)
If you've got a sound card with a speaker output (most current cards only have a headphone/line out) then you can connect any ordinary hi-fi speakers, including the little M4s, with an appropriate 1/8th-inch-to-bare-wires lead.
Otherwise, you'll need an outboard amplifier. Any old integrated amplifier or receiver will do, though; a $20 second hand receiver of dubious provenance would be fine, and it's easy to find those.
And a receiver gives you a radio tuner, too!
I bought a Hercules Prophetview 720 LCD monitor, but the power adapter was not included, and when I went back to the store it had shut down.
I have been looking for a month now for a power adapter, and NO ONE carries them here. I was recommended to go online but I still can't seem to find a site where I can just buy an adapter. I've tried every AC adapter I could find, but they don't fit.
Looking at the specs for the monitor, it would appear that the power adapter's a plain 12 volt DC unit, which simplifies things. So if you can't get yourself the official power supply as a spare part, you should be fine with any 12 volt power adapter with at least a two-amp rating and the right plug on it. You'll want it to be a regulated supply, to be on the safe side.
I don't know, off the top of my head, what size of barrel plug the PV720 uses ("a fairly fat one" is the best I can do, and that's not quite a technical description of the connector). If it's one of the larger standard sizes, you'd probably be OK with one of the numerous plugs that come with a lot of plugpacks. If it's non-standard then that's more of a pain, but a small amount of warranty-voiding by anyone handy with a soldering iron and a rotary tool will allow a solid connection to be made. Any half-competent TV repair person should be able to deal with this problem, as should various other electronics people.
I'm reliably informed that beer is the recognised currency for getting electronics people to help you out in these situations.
I was a little bit surprised by your letters column where you told a guy that if he worried about paying for 15W being consumed by a monitor on standby he wouldn't be able to afford the computer in the first place.
I think that wasn't the point of the Energy Star standard, it was about millions of people leaving their monitors on standby instead of having them burning full power all the time.
I didn't like that you actually advised the guy to leave the monitor on standby!
I can't believe how lazy people are. The power button on my monitor is five inches away from my pinky finger as I'm writing this, I'm not going to die if I turn off the monitor as the computer shuts down.
That kind of laziness is going to cost us a lot of pain in the future. Coal ain't a renewable resource and renewable energy resources aren't going to be able to meet our needs. Leaving monitors on standby, printers on standby and anything that is standby capable on, we're just digging our own tomb.
Maybe today 15 watts is nothing, in 10 years it could be life or death (I'm exaggerating, but 10 million monitors burning 15 watts while doing nothing is significant).
How much things cost to run was, indeed, not the point of the Energy Star standard, but it was the point of Peter's question in column #8. He was asking whether monitors in standby would make a significant impact on the power bill. They won't. Not even in countries with expensive electricity, much less here in swimming-in-anthracite Australia.
Also, for the record, I didn't tell Peter to leave monitors in standby mode. I just told him how much power they could be expected to consume if he did.
The world in general and Australia in particular have awesome amounts of coal and natural gas. We're also consuming fossil fuels at a fantastic rate, of course, but the planet's coal and natural gas reserves can reasonably be expected to last for several decades more, and quite possibly well over a century. The problem is not scarcity of stuff to burn; it's what's emitted when you do it.
An unremarkable 17-inch CRT these days is likely to consume about 80 watts when it's on (that's quite a lot less power than a ten-year-old 17-inch CRT's likely to consume, by the way), and less than three watts when it's in standby. Let's be pessimistic, and assume exactly three watts; that's still only 3.75% of its on power. One hour on consumes as much power as almost 27 hours off.
If you're daft enough to plug a monitor in and just leave it in three-watt power-save for a year, it'll suck down a bit more than 26 kilowatt-hours in that year. At 15 to 20 Australian cents per kilowatt-hour, that'll cost from about four Australian bucks to a bit more than five. $AU5 is about $US2.80, as I write this.
For price and environmental-impact comparison purposes, a steam iron used for one hour per week will account for something in the order of 50 kilowatt-hours per year. A clock radio left on all day every day will consume a bit less than that. A household refrigerator will probably eat 600 to 700 kilowatt-hours per year. And, more relevantly, powering up a whole computer for four hours per day can be expected to account for something between 300 and 500 kilowatt-hours per year, depending on the PC.
Incidentally, when you turn a monitor on, its auto-degauss is likely to draw more than 500 watts, but only for 0.1 to 0.2 seconds. That isn't a significant factor in the equations, therefore; the degauss pulse would only be enough to power the monitor in standby for about 15 seconds to about a minute, depending on how ferocious that particular degauss is.
What all this means is that while it's perfectly sensible to turn monitors off manually when they're not in use - why suck down three watts when you don't have to - it really doesn't matter much, compared with the other things eating electricity in typical homes and offices. Remember to turn off the hundred-watt bulb in the bathroom instead of leaving it on for an hour, and you've saved about as much power as a standby-mode monitor will consume in a day and a half. And, as I mentioned, people who're going to be using electricity for heating anyway might as well leave their PCs on all the time, since they're just as efficient at warming up the air, but do something useful with the power as well.
For a while now I have had a nagging curiosity about really big strange-looking things which do stuff to electricity. But as you have just guessed, I haven't actually gone about learning anything. Because I have no idea where to start.
There are some strange-looking things on telegraph poles. I want to know what they do. There are some strange-looking things behind the chain-link fence with the danger signs on it. Any help will be appreciated, in an entirely Platonic way.
And since I still have your attention - I was looking at upgrading my audio equipment. I was thinking on blowing a little over $AU1000 on a Sony package which came with 5 speakers, sub, and the receiver. All the fancy DVD and tuner bits could come later when I wasn't completely broke.
Is this the best idea? If I gave you a grand to make something sound good, what would you do?
On the stereo-system subject, you'll get a better sounding system for the same money if you invest a bit more effort. It depends on how important the different components are to you.
If you don't have a DVD player at the moment, and if you'd really like one, then dropping a few bucks on one of the all-region cheapies you can get these days is not at all a bad idea. Get a cheap surround receiver to go with it (see here, for instance, or cruise for an even cheaper second-hand unit), and you've got the core of a really rather good surround system. The DVD player works as a CD player, and the receiver has a tuner in it, so you've got those functions covered as well as the movie-playback features.
You still need speakers, of course. A simple stereo pair will do for starters; I'm very impressed with the quality of the kit speakers I recently reviewed, and a pair of those will only cost you another $198 plus shipping. Bingo, there's your thousand-buck budget, if you went for a new surround receiver.
This only gives you stereo, but it'll give you quite good stereo, which beats the hell out of crappy surround. As soon as you manage to stump up another $AU300, you can expand to five-speaker surround by buying three more M4 kits; if you want more bass and can live without surround for a while, you could get a passive subwoofer (a sub without a built-in amplifier) at this point instead.
Or, alternatively, you could scrounge around for second-hand speakers. $AU200 ought to buy you two really rather good second hand speakers. Or three pairs of speakers of more dubious parentage, which you could set up as a quite passable, though probably funny-looking, surround arrangement while you save for something better.
Where could i find Hats similar to the ones that fidel castro was seen wearing? Ive searched hundreds of sites, and cannot find the hat. It is the flat topped cap that is camoflaged. All i can find are berets and propeller beanies :) Do they still sell or make these hats? My friend says he got one from china.
You people are laughing at me, not with me, aren't you?
As proof that If I Don't Know It, My Readers Do, though, it would appear that Fidel's classic hat is a "summer BDU cap". It was, apparently, standard issue for US soldiers until 2001. Army surplus stores or pawn shops outside military bases should, I'm told, be able to provide you with the cap in question, for less than $US5.