A quick websearch leads to a lot of different explainations for why IBM picked the 8088 over the 68000. Some of the reasons I just found are IBM having a large supply of the intel chips on hand, IBM having a pre-existing arrangement with intel where they gave intel rights to their bubble memory in exchange to rights to the 8088 (that doesn't make much sense), and 68000 required more expensive support hardware. I didn't find any sites mentioning my explaination, but that's what I read in the early 80's when it was happening.
IBM designed the PC around the Motorola 68000 cpu, but when they were ready to start production, they found out the 68k was physically too big for their fabrication equipment, so they had to switch to the smaller and inferior Intel 8088. When they switched they also added circuity to kludge the 8088 into their design, and that kludge was eventually incorporated into the 286 and the legacy of it is still with us.
The design for the CPU though was and still is Intel's.
What does this have to do with ohm's law?
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Ohm's law is "voltage dropped across a load is directly proportional to the current through the load, for a constant load". What does this have to do with the law the article talks about?
From the article: The fog screen enables many novel applications indoors. Interesting applications include walk-thru advertisements on shops or malls, or a walk-thru screen in world-class museums, corporate showrooms, trade fairs, theme parks, special events, spas, theatres, science centers, lobbies, etc. We can extend the technology to limited outdoor usage.
Does anyone else find it find it very disturbing that the first application they suggest is advertising?
How do you know that just because you can't make calls or see anything on the screen the phone is really off? It might even have a small internal battery that charges off the main battery and powers the tracker when the main battery is disconnected.
But it includes processing. If the disposable film camera is $5, that means you have to find a place that will develop it for $6 including the CD. I don't know of anywhere to get film developed that cheaply.
Why do people buy books that claim to be aimed at dummies? Just because you're a novice doesn't mean you're a dummy. The computer books are also very condescending, the tone of them is talking down to the reader. The Sams TY series are much better for new users.
The Photon does use a resistor. All batteries have an internal resistance, and for those crappy little watch batteries, it's high enough to limit the current to the LED. Also, those are 3 volt lithium batteries so you are still using double the voltage needed, and lithium batteries have a flat discharge curve.
An alkaline battery fluctuates from 1.6 to 1.2 volts over its life time, a White LED typically drops 2.9 volts, so if you use 2 alkalines in series, you'll start with 0.3 volts dropped across the resistor, so the LED will fluctuate from full brightness to nothing in half the battery life. That is wasteful. If you use 3 batteries, you'll start with 1.9 volts dropped across the resistor, when the batteries are half used up, you'll still have 1.3 vols dropped across the resistor so it's at 2/3rd brightness. When the batteries are fully used up, you're still getting light. That is more effecient.
The datasheet is right here for NiMH. That is a very flat horizontal curve until the cliff right at the end. For comparison, the Alkaline curve is here (look on page 2). That curve drops steadily throughout the life.
You seem to be circling the point, but just don't get it. Here's a few hints:
The voltage drop of the LED is unrelated to the voltage of the battery; the battery voltage just needs to be greater than the drop across the LED for the LED to light.
For a given brightness of LED, the current needs to be the same; it wouldn't be enormous for a higher voltage. In theory, the LED is a short circuit anyway, to the current is whatever the battery can put out regardless of voltage (at least for the split second until the LED fries.
There is a current limiting resistor in series with the LED, which according to Kirchov's voltage law has the rest of the voltage dropped across it. So in that case, you know the resistance and voltage dropped across the resistor, therefore you know the current through it, and by Kirchov's current law, you know the current through the LED.
Now, it should be fairly obvious that the larger the voltage dropped across the resistor, the more stable the current will be against slight changes in battery voltage. Therefore, you want a relatively large voltage potential dropped across the resistor (at least as much as across the LED) to keep the current stable. That means the voltage of the battery should be at least double the voltage drop of the LED.
It's too bad the moderators marked this BS informative.
NiCd and NiMH batteries hold their terminal voltage until almost completely discharged too, they are both actually slightly better than Li-ion in that respect. They will also work will at current draws of up to 1C for NiCd and 2C for NiMH with no loss of performance.
The Lithium batteries that can do 2.5Ah @ 3.6 volts in an AA form factor aren't even rechargable.
The NiMH rechargable batteries last about twice as long in a digital camera than the best alkalines.
An AA alkaline has about 3 amp-hours of charge, and the NiMH has about 1.7, but you only get the full amount of power if you discharge the battery slowly. A digital camera draws about 1 amp, and the high current drain is too much for an alkaline battery. NiMH batteries can easily handle the drain. At 1 amp, a 3Ah alkaline won't even last 1 hour, but the 1.7Ah NiMH will last pretty close to the 1.7 hours. The energizer website has some nice graphics of battery life vs current drain for all the kinds of batteries they make.
The only real downside to NiMH batteries is they will self-discharge in about 3 weeks, and they don't deal well with just sitting around for months at a time, so they're only good for things that are used a lot.
A good guideline is if the alkaline batteries last less than 6 months, use NiMH instead, but keep in mind you'll have to recharge them every 3 weeks.
Now you must buy the whole thing again for a new stick.
The whole thing costs a fraction of what a new stick for the atari cost, and that doesn't even take into account 20 years of inflation.
These games are great for the $10-$20 they cost. If they were built like the old atari stuff, they'd cost $50 like the old atari joysticks and then very few people would buy them.
It's funny how there seems to be such a strong anti-robot attitude here. Asimov's robot stories always took place in a world that was afraid of robots. Everyone I know who's read his books found that strange but it looks like he was right after all.
There is no such thing as He2. Helium has a full valence shell so it's natural state is just He. Do you think that putting 2 after an element symbol means "gas" or "elemental"?
As for the halon, there are various type of varying degrees of 'badness'.
Halon is a CFC. It is mildly toxic to humans, but very destructive to the ozone layer. When halon is heated (say during a fire when), it becomes extremely toxic to humans, just like freon.
Actually, I'm using the fact that the University of Waterloo is a 40 minute plane ride from Toronto where we connect to the backbone. The round trip is 80 minutes. We ignored the time it takes to write and read the discs.
So you're using those [RM]IAA 'equivalent' CD-burners?
But that's one specific application; transferring large files. In the general case, you can't replace an internet connection with a high latency connection no matter how great the bandwidth. The point of the exam question was to emphasize the difference between latency and throughput.
On our Distributed Systems final, we had a question about using an airplane full of CDs being used to replace our school's internet connection. The point was the even though the plane offered 10,000 times more bandwitdh, the 80 minute latency meant it wasn't a viable replacement.
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A quick websearch leads to a lot of different explainations for why IBM picked the 8088 over the 68000. Some of the reasons I just found are IBM having a large supply of the intel chips on hand, IBM having a pre-existing arrangement with intel where they gave intel rights to their bubble memory in exchange to rights to the 8088 (that doesn't make much sense), and 68000 required more expensive support hardware. I didn't find any sites mentioning my explaination, but that's what I read in the early 80's when it was happening.
Jason
ProfQuotes
IBM designed the PC around the Motorola 68000 cpu, but when they were ready to start production, they found out the 68k was physically too big for their fabrication equipment, so they had to switch to the smaller and inferior Intel 8088. When they switched they also added circuity to kludge the 8088 into their design, and that kludge was eventually incorporated into the 286 and the legacy of it is still with us.
The design for the CPU though was and still is Intel's.
Jason
ProfQuotes
It will be interesting to see what they try next.
Maybe claim that since they created the x86 platform, the Opteron contains their IP and any Opteron users owe them $750/CPU in licensing.
Jason
ProfQuotes
Ohm's law is "voltage dropped across a load is directly proportional to the current through the load, for a constant load". What does this have to do with the law the article talks about?
Jason
ProfQuotes
From the article: The fog screen enables many novel applications indoors. Interesting applications include walk-thru advertisements on shops or malls, or a walk-thru screen in world-class museums, corporate showrooms, trade fairs, theme parks, special events, spas, theatres, science centers, lobbies, etc. We can extend the technology to limited outdoor usage.
Does anyone else find it find it very disturbing that the first application they suggest is advertising?
Jason
ProfQuotes
How do you know that just because you can't make calls or see anything on the screen the phone is really off? It might even have a small internal battery that charges off the main battery and powers the tracker when the main battery is disconnected.
Jason
ProfQuotes
But it includes processing. If the disposable film camera is $5, that means you have to find a place that will develop it for $6 including the CD. I don't know of anywhere to get film developed that cheaply.
Jason
ProfQuotes
Why do people buy books that claim to be aimed at dummies? Just because you're a novice doesn't mean you're a dummy. The computer books are also very condescending, the tone of them is talking down to the reader. The Sams TY series are much better for new users.
Jason
ProfQuotes
The Photon does use a resistor. All batteries have an internal resistance, and for those crappy little watch batteries, it's high enough to limit the current to the LED. Also, those are 3 volt lithium batteries so you are still using double the voltage needed, and lithium batteries have a flat discharge curve.
An alkaline battery fluctuates from 1.6 to 1.2 volts over its life time, a White LED typically drops 2.9 volts, so if you use 2 alkalines in series, you'll start with 0.3 volts dropped across the resistor, so the LED will fluctuate from full brightness to nothing in half the battery life. That is wasteful. If you use 3 batteries, you'll start with 1.9 volts dropped across the resistor, when the batteries are half used up, you'll still have 1.3 vols dropped across the resistor so it's at 2/3rd brightness. When the batteries are fully used up, you're still getting light. That is more effecient.
Jason
ProfQuotes
Mouse buttons have a horrible tactile feel for trying to enter morse code. Even using a keyboard key would be a lot better.
Jason
ProfQuotes
What do you think you're talking about?
The datasheet is right here for NiMH. That is a very flat horizontal curve until the cliff right at the end. For comparison, the Alkaline curve is here (look on page 2). That curve drops steadily throughout the life.
Jason
ProfQuotes
- The voltage drop of the LED is unrelated to the voltage of the battery; the battery voltage just needs to be greater than the drop across the LED for the LED to light.
- For a given brightness of LED, the current needs to be the same; it wouldn't be enormous for a higher voltage. In theory, the LED is a short circuit anyway, to the current is whatever the battery can put out regardless of voltage (at least for the split second until the LED fries.
- There is a current limiting resistor in series with the LED, which according to Kirchov's voltage law has the rest of the voltage dropped across it. So in that case, you know the resistance and voltage dropped across the resistor, therefore you know the current through it, and by Kirchov's current law, you know the current through the LED.
Now, it should be fairly obvious that the larger the voltage dropped across the resistor, the more stable the current will be against slight changes in battery voltage. Therefore, you want a relatively large voltage potential dropped across the resistor (at least as much as across the LED) to keep the current stable. That means the voltage of the battery should be at least double the voltage drop of the LED.Jason
ProfQuotes
It's too bad the moderators marked this BS informative.
NiCd and NiMH batteries hold their terminal voltage until almost completely discharged too, they are both actually slightly better than Li-ion in that respect. They will also work will at current draws of up to 1C for NiCd and 2C for NiMH with no loss of performance.
The Lithium batteries that can do 2.5Ah @ 3.6 volts in an AA form factor aren't even rechargable.
Jason
ProfQuotes
The NiMH rechargable batteries last about twice as long in a digital camera than the best alkalines.
An AA alkaline has about 3 amp-hours of charge, and the NiMH has about 1.7, but you only get the full amount of power if you discharge the battery slowly. A digital camera draws about 1 amp, and the high current drain is too much for an alkaline battery. NiMH batteries can easily handle the drain. At 1 amp, a 3Ah alkaline won't even last 1 hour, but the 1.7Ah NiMH will last pretty close to the 1.7 hours. The energizer website has some nice graphics of battery life vs current drain for all the kinds of batteries they make.
The only real downside to NiMH batteries is they will self-discharge in about 3 weeks, and they don't deal well with just sitting around for months at a time, so they're only good for things that are used a lot.
A good guideline is if the alkaline batteries last less than 6 months, use NiMH instead, but keep in mind you'll have to recharge them every 3 weeks.
Jason
ProfQuotes
Now where'd I put that DivX of Days of Thunder.
Jason
ProfQuotes
Now you must buy the whole thing again for a new stick.
The whole thing costs a fraction of what a new stick for the atari cost, and that doesn't even take into account 20 years of inflation.
These games are great for the $10-$20 they cost. If they were built like the old atari stuff, they'd cost $50 like the old atari joysticks and then very few people would buy them.
Jason
ProfQuotes
The rest goes to the lawyers. Isn't mass tort law great?
Jason
ProfQuotes
With all the crap sony's media arms have been pulling, no self-respecting slashdotter would buy any sony product.
Jason
ProfQuotes
Yes, but you only get paid for 8 hours/day, so as far as the company is concerned, that'll all you contribute.
Jason
ProfQuotes
It's funny how there seems to be such a strong anti-robot attitude here. Asimov's robot stories always took place in a world that was afraid of robots. Everyone I know who's read his books found that strange but it looks like he was right after all.
Jason
ProfQuotes
I think you are thinking of He2.
There is no such thing as He2. Helium has a full valence shell so it's natural state is just He. Do you think that putting 2 after an element symbol means "gas" or "elemental"?
As for the halon, there are various type of varying degrees of 'badness'.
Halon is a CFC. It is mildly toxic to humans, but very destructive to the ozone layer. When halon is heated (say during a fire when), it becomes extremely toxic to humans, just like freon.
Jason
ProfQuotes
Actually, I'm using the fact that the University of Waterloo is a 40 minute plane ride from Toronto where we connect to the backbone. The round trip is 80 minutes. We ignored the time it takes to write and read the discs.
So you're using those [RM]IAA 'equivalent' CD-burners?
Whis is the MIAA?
Jason
ProfQuotes
But that's one specific application; transferring large files. In the general case, you can't replace an internet connection with a high latency connection no matter how great the bandwidth. The point of the exam question was to emphasize the difference between latency and throughput.
Jason
ProfQuotes
On our Distributed Systems final, we had a question about using an airplane full of CDs being used to replace our school's internet connection. The point was the even though the plane offered 10,000 times more bandwitdh, the 80 minute latency meant it wasn't a viable replacement.
Jason
ProfQuotes
I thought it was a sequel to the Sandra Bullock movie, 28 Days.
Jason
ProfQuotes