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the power supply in the pc has only internal connectors for your cdrom drive, floppy, etc. so when you use an external device, like a scanner, cable modem, network hub, etc., you wind up needing an AC socket for each of these, AND a AC-to-DC "block" that is often difficult to plug in to a powerstrip.
all those things that use blocks are looking for DC power. since the powersupply in the cpu is already creating DC for the internal parts, we should be able to plug any other DC device into the computer case. this would get rid of lots of blocks, save lots of wall sockets, and make the wirey mess below the desk much more orderly. also saves manufacturing cost.
wall wart replacement
http://www.halfbake...0wart_20replacement
very similar idea posted a mere fortnight ago by [breadlover] [krelnik, Oct 04 2004]
PC cigarette lighter adapter kit
http://store.frozen...ozencpu/cig-01.html
You can use this to power external peripherals [kropotkin, Oct 04 2004, last modified Oct 21 2004]
[link]
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PCs all used to have AC outputs for monitors, but I think these were removed for safety reasons (does anyone know why?). With USB, you can run most peripherals (scanners, external modems, digital cameras) powered through the USB link, but I guess printers and speakers need more power than USB can deliver. |
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The monitor outputs were removed because they can't safely handle the power needs of modern SVGA monitors. They only had enough juice for the early monochrome jobs. |
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IBM Aptivas (circa 1997) have a DC power socket that provides 12 volts. Could power speakers, etc. |
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You can buy small cards that go into a PC slot for a few dollars to achieve this. Voltage is adjustable. I've a few spare ones! |
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Failing that, a USB port is good for 5 volts at half an amp. How do you think those USB 'phone chargers work? |
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These used to be available from electronic supply shops in Australia as a kit. It was a small card that took power from a drive adapter, and provided 3, 5, 6, 9 and 12 volts at a PCI slot cover. I'm looking for a link now. |
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I agree it's annoying, but there's not a good standard connector because there are no standard voltages. In my own collection of "wall wart" (block) power supplies, they supply such a wide variety of voltages (3V, 4.5V, 6V, 7.5V, 9V, 12V, 15V, etc.) required by the various devices, and such a wide variety of power (0.1W for something like a little mouse, up to 13W for my big printer), plus some devices want DC power, some want AC.
Another issue is that it complicates things with regard to the internal power supply, if that's where the power is coming from. Accidentally shorting the "peripheral" power outlet is likely to cause such a transient as to cause a data error in the CPU, memory, disk drive heads, etc. And without careful use of resetable solid-state fuses, you run the risk of overloading the internal power supply's capacity.
Futhermore, how would this work with notebook computers, which account for nearly 1/3 of PC sales now? I suppose the peripheral could *either* be powered from the AC brick (notebook mode) or the "peripheral" power connector on the PC (desktop mode).
I like the idea... it just needs further work methinks. |
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