AC-DC is also pretty efficient, and yes, it can be 95% (take a look at "90 plus" computer PSUs).
But nothing beats AC-AC. An autotransformer (like the ones on the street. In my country they're 13,2kV->220V) can yield 99% efficiency... when talking about 100kVA:P
I also forgot to mention, GGP talked about a "BIG" ac-dc unit. This isn't efficient. You see, DC-DC converters are only efficient when running at nearly 100%. Less than that and their efficiency drops. Take a look at the "buck circuit". It's a switching transistor with a low pass filter (an inductor). If operating at almost 100% load, the transistor conducts all the time and energy is only wasted by the inductor's own resistance. At lower loads, the transistor is constantly closing and opening. FETs are really efficient (a FET's leads have more resistance than the silicon when conducting), but only when fully conducted. When they're switching - and especially at a high frequency (the higher the frequency, the smaller the inductor), they waste a lot of energy switching on and off (during the switch on/switch off times there is a resistance).
So, there are a lot of things to consider, but in the end, the PSU is efficient ONLY at the specified rate, outside that rate it's inefficient, and without load it won't even regulate. So no, you can't have a "big" AC-DC unit unless you have 50 workstations hooked to it all the time. It works for a computer lab, but it doesn't work for a house, where load is highly variable and unpredictable.
go to your car, grab both battery leads. feel anything? yes, about that safe. Ohm's law says you can't have 10A 12V running through your body (resistance is too high).
Now, for the wire gauge, again, take a look at your car battery, and now go to your house and remove the circuit breaker's box cover and take a look at the wires there. that should give you an indication
yes but you still need converters at everything. you can send, say, 48VDC down the line but every electronic gadget will need to convert it to 12, 5, 3.3, 1.2, whatever voltage it needs. Net gain will be zero, and no one in their right mind would rewire a house just for that. you can't send low voltage DC for the whole house. the huge current will kill it. and if you send 48VDC, nothing keeps chinese manufacturers from making low efficiency converters. hell, at 48VDC they would probably add a resistor and a zener diode to regulate power.
besides, things that make a difference in your electric bill are heaters, air conditioners, fridges...things that run great on AC power.
I never get a reliable 3G connection anyway. It keeps jumping from H (HSDPA) to 3G (?) to G (GPRS?!), even in downtown areas. Outdoors, of course. Sometimes I get a pretty good data connection and then it suddenly dies. Can't use it at all while moving. I don't know if it's supposed to be like that or if I have a problem with my phone, or what. Many people do use 3G modems to browse the web and these are OK as long as you stay near a window.
I'm pretty sure GSM data (HSDPA) consumes way much more power than wi-fi. My Milestone gets warm after a few minutes of browsing the web with HSDPA and the battery starts to drain really quick. If I browse via Wi-Fi the phone stays cool.
Interesting. In Argentina we have a (roughly) 50% import tax, which include all federal taxes (21% IVA. English:VAT), shipping cost taxed too. Computers, or electronic components that "run" on electricity (including: computers, excluding: cables) are taxed at 10,5% and sometimes even less (books are not taxed).
Still, things are 400% more expensive than in the USA. We don't have apple stores, only importers (MacStation, to name one) which handle all the work themselves.
I don't think the Via-Miami shipping adds that much. I mean if it wasn't for that, I doubt we'd get the products in the first place. The USA is a market 100 times larger than latin america. I doubt they would ship directly from China to us. They do that for things like fans, toys, things you can fill dozens of containers with. Not with top notch computers. If it's not Via-Miami then it would be Via-Brazil, to Argentina, Uruguay, etc. Don't forget, Chile does that (Iquique), like Miami but for the pacific coast.
I doubt any country has 400% import taxes. I thought the same about US shipping but it's really not the case. I was told these things arrive via Miami, which is a free trade zone. Meaning things that arrive there and are sent to other countries are not subject to US taxes. I dont know if this is true, but seems logical.
Anyway many things going through Brazil go through Ciudad del Este, Paraguay (another free trade zone). CDE is a little city full of every electronic gadget out there. Back in the day it was amazing - you could go and buy electronics at half price. I remember buying a NES, SNES, National M7 camcorder. All of this in the early 90s. Curiously most National products (Made in Japan, Matsushita electric: National, Technics, Panasonic, all the same) and Sony things (Japanese too) came with manuals in Arabic (Whatever: that script they use which looks like random swirly lines).
That thing you mention doesn't happen in countries where piracy is high. I live in Argentina, and I WISH I could get the matrix trilogy for $9. Or even $50 (the trilogy would cost me $100). I know they don't have $5 bins (except really truly bad crap like a macarena remixes CD).
Good for you. Where I live CD prices have stayed the same. A CD in 1999 would cost you USD 22. Today it costs roughly USD 22. Our income hasn't increased 4x but our money has been devaluated to 1/4 of what it was.
Back in the time, I used to buy my CDs for $10-$12 from USA. Even paying international shipping it was cheaper for me.
Things are much more expensive, in USD, outside USA. A Playstation 3 costs USD 800 down here in Argentina. Games are priced at over $100. It's not about taxes either. The rationale is this: "People are going to pirate. We don't have a chance to sell to middle and lower classes, only higher classes. And we can charge a lot more if we market it as a 'luxury' item".
Agreed with that. I've seen ads in DVDs for rent. I thought... well, ok, it's a rental, I'm only gonna watch it once so i don't care.
Then my dad bought a DVD of a Rolling Stones concert. Guess what? The moment you start it, a 1-minute ad starts playing. You can't skip it. What the hell? If I PAY for something, I don't want to be forced to watch an ad! If it's a (paper) magazine I can skip the pages, but this is way too much.
Jesus wanted to convince us that there is a god and there is salvation, through him. Atheists want to convince us that there is no god and there is "freedom", through them.
Truth is, atheists are all douches who have no respect. I'm a scientist but I decided to have faith. I'll be damned (see what I did there?) if I let someone else talk me out of it.
Heck, it was one of the nails in the HD-DVD coffin during the HD-DVD/Blu-Ray battle. Theatres in other countries were suddenly finding less customers because it was cheaper and better to just import the HD-DVD that go to the theatre, OR the movie wasn't out in theatres yet!
Maybe theatre operators were charging way too much? I mean if buying a BD/HDDVD ($39/$19.99 on amazon + shipping) is cheaper than a movie ticket AND ALSO the cost of early HD-DVD players was taken into account...
Come on, your explaination is ridiculous. Besides, most hollywood blockbusters (the kind of thing that makes up for what "most people watch") are released worldwide within weeks. Hell, most movies are first released here in Argentina before USA, because releases here are Thursdays and in most of the world they're on Friday.
What nerds here don't seem to understand is that going to the theater is not about just "watching a movie". It's about going out (a strange concept to most slashdot readers, it seems), maybe on a date, maybe take your kids to the movies. It's a social activity.
Yes, only it doesn't work that way. Just a tiny fraction would be importing the product.
Guess what: music companies outside the US didn't go out of business when Amazon/CDNow/CDUniverse/whatever started selling worldwide at cheaper prices (including shipping).
Yeah, also if you send the ticket to the INCAA (national cinema institute) you can win $10.000 every month.
Anyway, cinema is the only "cheap" thing. An xbox 360/PS3 is $800. 3mbps ADSL connection, $30 a month. Anything electronic or high tech, USA price multiplied by 3 or 4 (they blame it on taxes, while tax is "only" 50%).
A Big Mac combo is about $8 (McDonald's is not for the average folk) -- for that money I can go to a local restaurant and have a steak, on a table, with a waiter serving me.
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AC-DC is also pretty efficient, and yes, it can be 95% (take a look at "90 plus" computer PSUs).
But nothing beats AC-AC. An autotransformer (like the ones on the street. In my country they're 13,2kV->220V) can yield 99% efficiency... when talking about 100kVA :P
I also forgot to mention, GGP talked about a "BIG" ac-dc unit. This isn't efficient. You see, DC-DC converters are only efficient when running at nearly 100%. Less than that and their efficiency drops. Take a look at the "buck circuit". It's a switching transistor with a low pass filter (an inductor). If operating at almost 100% load, the transistor conducts all the time and energy is only wasted by the inductor's own resistance. At lower loads, the transistor is constantly closing and opening. FETs are really efficient (a FET's leads have more resistance than the silicon when conducting), but only when fully conducted. When they're switching - and especially at a high frequency (the higher the frequency, the smaller the inductor), they waste a lot of energy switching on and off (during the switch on/switch off times there is a resistance).
So, there are a lot of things to consider, but in the end, the PSU is efficient ONLY at the specified rate, outside that rate it's inefficient, and without load it won't even regulate. So no, you can't have a "big" AC-DC unit unless you have 50 workstations hooked to it all the time. It works for a computer lab, but it doesn't work for a house, where load is highly variable and unpredictable.
If you're delivering a "safe" DC voltage, say 48V, you need to accomodate for higher currents.
10A 48V is "only" 480W.
go to your car, grab both battery leads. feel anything? yes, about that safe. Ohm's law says you can't have 10A 12V running through your body (resistance is too high).
Now, for the wire gauge, again, take a look at your car battery, and now go to your house and remove the circuit breaker's box cover and take a look at the wires there. that should give you an indication
yes but you still need converters at everything. you can send, say, 48VDC down the line but every electronic gadget will need to convert it to 12, 5, 3.3, 1.2, whatever voltage it needs. Net gain will be zero, and no one in their right mind would rewire a house just for that. you can't send low voltage DC for the whole house. the huge current will kill it. and if you send 48VDC, nothing keeps chinese manufacturers from making low efficiency converters. hell, at 48VDC they would probably add a resistor and a zener diode to regulate power.
besides, things that make a difference in your electric bill are heaters, air conditioners, fridges...things that run great on AC power.
I never get a reliable 3G connection anyway. It keeps jumping from H (HSDPA) to 3G (?) to G (GPRS?!), even in downtown areas. Outdoors, of course. Sometimes I get a pretty good data connection and then it suddenly dies. Can't use it at all while moving. I don't know if it's supposed to be like that or if I have a problem with my phone, or what. Many people do use 3G modems to browse the web and these are OK as long as you stay near a window.
I'm pretty sure GSM data (HSDPA) consumes way much more power than wi-fi. My Milestone gets warm after a few minutes of browsing the web with HSDPA and the battery starts to drain really quick. If I browse via Wi-Fi the phone stays cool.
Interesting. In Argentina we have a (roughly) 50% import tax, which include all federal taxes (21% IVA. English:VAT), shipping cost taxed too. Computers, or electronic components that "run" on electricity (including: computers, excluding: cables) are taxed at 10,5% and sometimes even less (books are not taxed).
Still, things are 400% more expensive than in the USA. We don't have apple stores, only importers (MacStation, to name one) which handle all the work themselves.
I don't think the Via-Miami shipping adds that much. I mean if it wasn't for that, I doubt we'd get the products in the first place. The USA is a market 100 times larger than latin america. I doubt they would ship directly from China to us. They do that for things like fans, toys, things you can fill dozens of containers with. Not with top notch computers. If it's not Via-Miami then it would be Via-Brazil, to Argentina, Uruguay, etc. Don't forget, Chile does that (Iquique), like Miami but for the pacific coast.
Ah netflix. I don't know what that is.
Or hulu. Or spotify. Or Lala. Or itunes. Or... well, you see the pattern.
Oh, I know what Steam is. My brother's credit card extension is very familiar with it.
I doubt any country has 400% import taxes. I thought the same about US shipping but it's really not the case. I was told these things arrive via Miami, which is a free trade zone. Meaning things that arrive there and are sent to other countries are not subject to US taxes. I dont know if this is true, but seems logical.
Anyway many things going through Brazil go through Ciudad del Este, Paraguay (another free trade zone). CDE is a little city full of every electronic gadget out there. Back in the day it was amazing - you could go and buy electronics at half price. I remember buying a NES, SNES, National M7 camcorder. All of this in the early 90s. Curiously most National products (Made in Japan, Matsushita electric: National, Technics, Panasonic, all the same) and Sony things (Japanese too) came with manuals in Arabic (Whatever: that script they use which looks like random swirly lines).
Ah, the good old days of Japanese manufacturing.
PS3 is not cracked? Where the hell do you live, dude? You can load the images to the PS3 hard drive and play.
OK, anyway, the XBOX 360 is also $800 and games are priced similarly.
That thing you mention doesn't happen in countries where piracy is high. I live in Argentina, and I WISH I could get the matrix trilogy for $9. Or even $50 (the trilogy would cost me $100). I know they don't have $5 bins (except really truly bad crap like a macarena remixes CD).
Good for you. Where I live CD prices have stayed the same. A CD in 1999 would cost you USD 22. Today it costs roughly USD 22. Our income hasn't increased 4x but our money has been devaluated to 1/4 of what it was.
Back in the time, I used to buy my CDs for $10-$12 from USA. Even paying international shipping it was cheaper for me.
Things are much more expensive, in USD, outside USA. A Playstation 3 costs USD 800 down here in Argentina. Games are priced at over $100. It's not about taxes either. The rationale is this: "People are going to pirate. We don't have a chance to sell to middle and lower classes, only higher classes. And we can charge a lot more if we market it as a 'luxury' item".
Not true at all, but they like to believe that.
Agreed with that. I've seen ads in DVDs for rent. I thought... well, ok, it's a rental, I'm only gonna watch it once so i don't care.
Then my dad bought a DVD of a Rolling Stones concert. Guess what? The moment you start it, a 1-minute ad starts playing. You can't skip it. What the hell? If I PAY for something, I don't want to be forced to watch an ad! If it's a (paper) magazine I can skip the pages, but this is way too much.
Unthinkable (with Samuel L Jackson and Carrie-Ann Moss).
The bomb guy disarms the bomb with a Mac running EXCEL, randomly pressing keys in different cells.
http://i.imgur.com/8SMhl.png
What? I can be a douche sometimes too.
http://en.wikipedia.org/wiki/Douche
Atheists feel like Jesus trying to save you ;)
Jesus wanted to convince us that there is a god and there is salvation, through him.
Atheists want to convince us that there is no god and there is "freedom", through them.
Truth is, atheists are all douches who have no respect. I'm a scientist but I decided to have faith. I'll be damned (see what I did there?) if I let someone else talk me out of it.
I wish I knew what the hell MTG players are talking about.
Signed: someone who sells MTG and owns a comic book shop where tournaments are held.
And I'm not kidding!
What's the difference on censorship or P2P filtering, and jamming someone else's phone?
You realize how much full of BULLSHIT slashdot readers are, after reading this thread. Not double-standard. Just bullshit.
You're getting 100mbps, which is unheard of in most parts of the world. You can still surf the web, download shit, do whatever the fuck you want.
But this is slashdot. Let the whining begin.
Maybe theatre operators were charging way too much? I mean if buying a BD/HDDVD ($39/$19.99 on amazon + shipping) is cheaper than a movie ticket AND ALSO the cost of early HD-DVD players was taken into account...
Come on, your explaination is ridiculous. Besides, most hollywood blockbusters (the kind of thing that makes up for what "most people watch") are released worldwide within weeks. Hell, most movies are first released here in Argentina before USA, because releases here are Thursdays and in most of the world they're on Friday.
What nerds here don't seem to understand is that going to the theater is not about just "watching a movie". It's about going out (a strange concept to most slashdot readers, it seems), maybe on a date, maybe take your kids to the movies. It's a social activity.
Yes, only it doesn't work that way. Just a tiny fraction would be importing the product.
Guess what: music companies outside the US didn't go out of business when Amazon/CDNow/CDUniverse/whatever started selling worldwide at cheaper prices (including shipping).
Yeah, also if you send the ticket to the INCAA (national cinema institute) you can win $10.000 every month.
Anyway, cinema is the only "cheap" thing. An xbox 360/PS3 is $800. 3mbps ADSL connection, $30 a month. Anything electronic or high tech, USA price multiplied by 3 or 4 (they blame it on taxes, while tax is "only" 50%).
A Big Mac combo is about $8 (McDonald's is not for the average folk) -- for that money I can go to a local restaurant and have a steak, on a table, with a waiter serving me.
Good thing that it's my comment what amuses you, and not TFA's study.
Anonymous prick.