Grounding isn't a substitute for the recieving end of a battery, not quite... I believe you could call that end of the battery the "circuit ground", which isn't really a ground at all, it's just the "negative" terminal. What I was talking about is "earth ground".Espozo wrote:Well, What kind of setup would something like the SNES do? Is it grounded somewhere? Or wait, aren't there two prongs on power outlet for the battery situation? (I don't know what to call it.) This is just what I'm confused about: Grounding is a substitution for having the flat side on a battery right? Didn't you say that you get now power or something if you ground, Khaz? I'm hopelessly confused.
He did it for fun, not to make an efficient computer. (I don't think anybody building a CPU at home is trying to make an efficient one?)Bregalad wrote:There is no reason to limit you to do that, because using many NAND gates where you could use another type of gate just slows down the circuit for no particular gain.rainwarrior wrote:I remember a while back Kevtris made a small computer entirely out of NAND chips: http://blog.kevtris.org/blogfiles/NANDputer/
Let's try explaining how an n-type MOSFET works...Espozo wrote:Also, what's the difference between a P Channel and an N Channel Mosfet? I see that both only have 3 prongs instead of 4, so I'm guessing it's how the 4 prongs are grouped to make 3.
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positive supply
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+-o|[--- positive supply
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input --+ +-- output
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+--|[--- negative supply
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negative supply
No idea, the ones that need it the most (due to consuming a lot) are the ones that almost never have it. It's pretty stupid in hindsight (I guess there must be some legal loophole somewhere). There's also the fact that extension cords rarely ever include the ground line so you may as well assume it doesn't exist...Khaz wrote:What has always confused me though is why some things make use of the ground pin on the wall outlet, and others don't. Why isn't EVERYTHING grounded like that?
It probably has something to do with explicit insulation of all exposed metal from contact with electrical components. (Source: Delta Machinery; Citizens Electric)Sik wrote:No idea, the ones that need it the most (due to consuming a lot) are the ones that almost never have it. It's pretty stupid in hindsight (I guess there must be some legal loophole somewhere).
Power strips and outdoor extension cords routinely include all three conductors, at least in NEMA markets.There's also the fact that extension cords rarely ever include the ground line so you may as well assume it doesn't exist...
As far as 1970s-level digital logic is concerned, all MOSFETs are like light switches:Espozo wrote:So are you saying that a p channel or an n channel mosfet will flip the value at the end? Or are you saying that the things on the sides that control if the main power goes through (I don't remember what they're called) have to be at different voltages relative to each other? I mean like on a p channel mosfet, they have to be the same to let the power go through, and on an n channel mosfet, they have to be different to let the power go through.
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n-MOSFET p-MOSFET
drain source
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gate ---|[--- body gate --o|[--- body
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source drain
While it is true that it took engineers a while to figure out how to put both n-MOS and p-MOS elements on the same physical die, I don't think that's what you're asking...Espozo wrote:How could there be both on a CMOS? (I'm not really getting this.)
Usually, but not always. The most egregious example that comes to mind is serial communications using RS-232, where "1" is -12V and "0" is +12V.Isn't the difference between them that the 1 is just at some higher voltage?
It varies a lot from device to device. In the 1970s through ... eh, 1993 or so, most things used 5V, but we've slowly reduced operating voltages down through 3.3V, 2.5V, 2V, 1.8V, 1.2V...is there a standard voltage for each that has been said, or does it vary from CPU to CPU?
So, it's basically the same thing except the body and the gate are flipped. (Except they aren't but I think you get what I mean) On a 3 pronged thing though, like I said, is it that the source and the body are connected, or is it that the source and the gate are connected?lidnariq wrote:n-channel MOSFETs conduct between the source and drain if the voltage on the gate is enough higher than the voltage on the body.
p-channel MOSFETs conduct between the source and drain if the voltage on the gate is enough lower than the voltage on the body.
I'm only talking about enhancement-mode MOSFETs. Please ignore depletion-mode MOSFETs for now...
Here's my ASCII art diagrams again:Code: Select all
n-MOSFET p-MOSFET drain source | | gate ---|[--- body gate --o|[--- body | | source drain
Well that's dumb. You can always connect two pins together, but you can't really take them apart.lidnariq wrote:It's actually kinda hard to get your hands on a discrete 4-pin MOSFET where all 4 parts are available to the user.
Hey I was thinking about that too.Khaz wrote:I've spent a lot of time trying to think of a way to design an entirely mechanical computer powerful enough to do any level of useful processing.rainwarrior wrote:You can make computers with any kind of switch. Mechanical switches, electromagnetic relays, even water has been used to create a computer. Usually we're talking aobut digital logic, but it's also possible to build an analog computer that can make use of the whole transfer function.
I know what a monstrosity Konrad Zuse's mechanical computers were, and from my understanding they read in paper tape and were mostly useful for floating-point calculations for bombing raids. But what if we could design a computer that had a mechanical motive force (say a crankshaft), and that could process in the same way a modern computer does? Enough to run, say, DOS (not that there'd be any point in DOS). I think that would be just downright fun to watch, if not educational and even theoretically useful.
I've heard people who talk of solar events in the distant past that were powerful enough to destroy electronic equipment, send surges through telegraph lines, etc... What if we had such a disaster today? What if something simultaneously fries every modern computer on earth?
Sure it's a long shot, but wouldn't it be cool to be somewhat prepared? I was also going to suggest a more physical storage medium too, on account of data on any magnetic surface would be wiped out, but then... That's what DVDs are good for, right? They're just physical pits on a flat surface, right? Hm.
I suppose no catastrophe out there is going to prevent us from using electricity again altogether... So it's really just data storage that's the worry. Unless we have a common-mode failure in a specific type of transistor or capacitor that's in basically every electronic device ever made, such that we can't even run our computers that make more computers and have to start from scratch.
*rambling*
