h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

i will pick this up better after som sleep.
only reason you would want to emulate electronic technology in the first place, would be to have sofware compatibility, eg able to transmit old serial bus style.

i will check before i sleep, but i am sure that electricity travels along standard track at two thirds the speed of light.

the "power light has no relation to a ninthe bit, in fact it has nothing to do with data at all.
the devices that manipulate the light, (so the resultant light, reflects the emulated electric signals.) would have to have at least one form of power.
this extra white light track, would be able to provide heat power and it is also a fuel for the data stream in as much as the emulated transistor could filter the right light color out of the white light to reenforce the color of the data, this is mainly about the fact that if you splil a light beam into 2 then you would need twice as much light to make them both shine as bright as the origional source.

as to the point of the light wheel.
i cant give a piont till i know what its called, then i can refresh my memory as to why it was rellevany.

no it doest need to be better at these things.
the technical specs never realy cross perform like that.

all that matters is the raw computing power at the end.
whilst the electronic system tries for gg hurts on ohhh you got it a "new" commercial 64 bitt bus.
what a load of tosh that is, when if we can even get it limping.
we could send a pulse of light a seconnd, thats 1 hurt right?
yet we could have a bus of 2,000,000 milion bits wide.
nothing to do with the amount of bits used in data propagation.
but that could also increase.
you could easily make thermal switches, ok from this stand point they would be a little large compared to our new pretty IC's n stuff.
and there are may forms of photo reactive material.
imean come on, all the money we spent on researching lcd displays and all that, when the very construct we designd, turned out to be similar to a substance in all cells.

"Piss on you you son ufa biaCH, ima going back to italy"

The speed of electricity through a wire is a bit of a complex question. It
depends on whether you are considering the rate at which electrons
themselves flow along a wire or whether you are considering the rate at
which an electrical signal passes along a wire.

In the first case, electrons themselves move quite slowly - about 100
micrometres per second (or, from another perspective, 1 metre in about 2.8
hours!) Clearly, this is not what we observe when we turn on a light switch.

Ideally, electricity moves at the speed of light. Imagine a tube full of
marbles. If you push a marble in at one end of the tube, another marble pops
out the other end almost instantaneously. Even if the individual marbles are
moving very slowly, the marble "wavefront" is travelling at a very high
velocity.

In the real world, things are not quite so tidy. Electricity flowing through
a gas, or having to work its way through electronic components such as
resistors or capacitors, can be slowed to speeds of 60 to 80 percent of
light speed. However, that's still fast enough that you can safely expect
the light to come on as soon as you flick the switch.

i dont truly understan,but i would say its better that electrin in a cable any day.


introduction
With modern inexpensive apparatus this previously almost impossible experiment can now be carried out to a good degree of accuracy in the school laboratory.

The experiment described here measures the speed of light through a polymer fibre optic cable using the timing capabilities of a fast PC based oscilloscope
Equipment required
A PC with PicoScope installed

An ADC-200/50 or ADC200/100 PC based oscilloscope

A fibre optic transmitter and receiver unit with a method of high frequency square modulation in the region of 250kHz to 1 MHz.

Suitable leads and connectors.

Ready made fibre optics apparatus is manufactured by Lascells Ltd and is available as product 280-216 from:


Technology Supplies Ltd.
Phoenix House,
Tern Hill,
Market Drayton,
Shropshire, UK.
Tel. 01630 637300.(UK) +44 1630 637300 (overseas)


This apparatus contains the transmitter and receiver with internal modulator together with monitoring sockets for the oscilloscope. Also included are a 5m and 20m fibre optic cable.
Background Theory
A solid state, square wave oscillator running at 1MHz will produce a signal with a 1us period and a square pulse lasting 0.5us. If this signal is used to modulate a light beam which passes along a fibre optic cable we get a pulse of light lasting 0.5us. A phototransistor can detect the pulse at the other end of the cable and convert it back into a pulse of electricity. The two electrical pulses (the original and the received one) can then be displayed on an oscilloscope screen. Since the light takes a finite amount of time to reach the receiver the second signal will be delayed in time ( dt ) and the received pulse will be shifted along the timebase axis. If we measure this shift it will tell us how long the light pulse took to travel the length of the fibre optic cable and hence the speed of the light can be calculated if the cable length is known.

Practical Considerations
1. Since light travels at about 300 million metres per second in air if our fibre optic cable is 30m long we would be looking for a time delay of 0.1us. A 50MHz (or better ) oscilloscope is required.
2. When we monitor the electrical pulses we are measuring the delay between transmitted and received electrical signals not the light pulses. If there is any time required for the conversion of light to electricity or vice versa then this would introduce errors into the calculation.
3. At high frequencies "square waves" become rounded due to stray capacitances and non-linear responses of the converters. The precise edge of the pulses is often lost.
Experiment Setup
Arrange the fibre optic system to transmit a high frequency modulated light beam along the cable which should be about 5m or so in length. Couple the receiver unit to the cable. Monitor the transmitted pulse at Channel A on the PICO ADC and the received pulse at Channel B.

The photograph shows the LASCELLS equipment connected as described and the results given later were taken from this apparatus. The PC oscilloscope settings are typically: Timebase 200ns/div, Channel A and B input +5V d.c., Trigger Single shot, rising to capture a pulse when GO is selected. Use a sensitivity of 400mVor so at various pre-trigger values.

Carrying out the Experiment
Switch on both the transmitter and receiver and select GO on the oscilloscope screen. Adjust the amount of pre-trigger and reselect GO until a trace is obtained which shows the "square" transmitted pulse and the received, much more rounded, pulse shifted to the right. When you are familiar with the pulse shapes, reset the timebase to as short a time possible to display the two leading edges of the pulses or the two trailing edges. Save and print out the screen image.



Switch off both units and replace the 5m cable with a 20m cable. Switch on again and repeat the experiment making timebase adjustments as required. Save and print again. You should find that the second print-out, with the longer cable, has a larger delay between the two pulses. (PicoScope rulers or automated measurements can be used here to help with the time measurement).



Calculations and Theory
If there are time delays in any part of the electronics then these delays should be the same for both experiments with the 5m and 20m cables. The only difference between the two experiments is that the light had to travel a further 15m in the second case. If we measure dt from each print-out then subtracting one from the other should give the amount of time taken to travel the extra 15m.

From the print-outs given using leading edges we get 0.55 us (-0.02) for the 5m dt

0.64 us (-0.01) for the 20m dt

i.e. 0.57 and 0.65

The difference between these two values is 0.08 us which is the time taken for the light to travel 15m.

The speed of the light is Distance/Time which is 15/0.08 x 10 ^ -6 which gives 1.9 x 10 ^ 8 ms-1

Yes, there are all kinds of photoreactive materials. We even have photoreactive transistors, called phototransistors. A light shining on the transistor biases it, switching it on.

But if you propose to use an LED to trigger a phototransitor, which then switches on an LED, which switches on a phototransistor, then I have to ask you this: why bother? A hybrid optical/electronic system would be much bigger, less reliable, more expensive, and slower than a purely electronic one.

no electric.
i know i wont be able to finish it myself yet.
buti think something like it may exist.
just by the by people.
i think the search for AI should be banned.
far too risky.
night all.

"Electricity flowing through a gas, or having to work its way through electronic components such as resistors or capacitors, can be slowed to speeds of 60 to 80 percent of light speed."

Yes. That's what is known as propagation delay. It's not that the electricity flows any slower, it's that it takes a bit of time for the next transistor in line to switch.

For example, if a circuit has been designed so that every time a particular switch is on, it increments the value of an array of transistors (a register, or buffer) consisting of 4 bits. So when switch A is turned on, counter B increases by one (0000, 0001, 0010, 0011, 0100, etc).

Here's the deal... the electrons that turn on switch A are not the same ones that come out of counter B. They are electrically isolated from each other. Imagine that we're talking about flows of water. A small stream going into switch A opens a gate that allows water to flow through A. A's flow turns a paddle wheel, and that paddle wheel turns and trips a series of levers that open other gates that allow 4 other, similar, small streams to flow, which represents our counter B.

A does not flow into B. A triggers flow within B. The water does not flow directly from A to B. That's how it works in electronics. The time it takes A to open that first gate, the water to rush out into the second stream, to turn that paddle wheel, trip those levers, open those gates, and get that water flowing into the other streams is the propagation time.

>> just by the by people.
i think the search for AI should be banned.
far too risky. <<

This from the guy who says we should fund scientists to do research into whatever they feel like.

Hmmm...I think we're getting a bit nmore of a flavour of what it's like to live in your world, Josef. With it's state-controlled music, means of production etc.

It's been tried before. It failed before.

RF

>> just by the by people.
i think the search for AI should be banned.
far too risky. <<

This from the guy who says we should fund scientists to do research into whatever they feel like.

Hmmm...I think we're getting a bit nmore of a flavour of what it's like to live in your world, Josef. With its state-controlled music, means of production etc.

It's been tried before. It failed before.

RF

Hey Gigglebane

Those little glass lightbulb thingys with the light operated fan inside i used to have one of them back in about 1964.
F19585?thread=452743&show=20&skip=0&lpcr=-1#p5612608
There were four vanes, like a paddle-wheel mounted on a compass-card type pointed vertical axis.
One side of each vane was painted white, the other black.
The glass enclosure was evacuated.

Light hits the white side and is reflected.
Light hits the black side and is absorbed.



result: the wheel spins, black side leading.


i thought everyone knew how that works
alec

Doesn't post 24 count as plagiarism?

http://www.picotech.com/experiments/speed_of_light/

But then, so is post 23:

http://www.madsci.org/posts/archives/may2001/988732797.Eg.r.html



(I thought the spelling had improved rather radically)

every one who went to school knows that maybee.
as to the plagerism, im not trying to pass it off as mine you ninny.
im trying to show the other guy that the brains of this world tend to agree.
light traveling down a single mode fibre is faster than electric on a data trak.
the whole thing was irrelivent anyway.
he was trying to explain how we are making faster and better electronic computers, and he didnt get the fact that speed is actually irrelivent.

its the bus band that makes all the differenc.
even as i said eirlier you only use a 1 pulse a second light beam
same data rate as a 1hz computer.
any yet you could tranfer a whole dvd's woth of data in that single burst.

where as pc's use 1 and zero with colour's you could represent entire command lines with a single color.. that is my point.

for those who are a bit to quick.

each command line that would be used would be pre defined as the most commonly used ones.

i theorise that if you had a million color strands you could embed them with data, then run themthrough a prism to become a single 'white light'
then at the other end prism again. hopefully the data will be preserved.
i know it still needs a huge amount of work, but then thats why we have scientists.

i am well aware of my own short commings, but i am highly disstressed to see just how much irrelivancy floats orund this sight.
you would think that if people wanted to talk about their fav band or their bloody cat or how long they can talk in the 3rd.
come on people, some of us dont want to grow old and die.
its not my place as i am just a short term visitor, but it seems to me things like that are probably better suited somewhere other than in the guide to the universe.

not the numptyverse as it seems to be when all the other brains sleep.

pleae forgive me for my last statement.
i forgat that you humans all go and get anebriated at the weekend.
some sort of farcical attempt and freedom and escapism no doubt.
your still gonna grow old and die though, no amount of 'fun' will make up for that when you are dead.

The 'fun' is what makes the trip worthwhile. We're all going to die.


'You know I'm born to lose, and gambling's for fools,
But that's the way I like it baby,
I don't wanna live for ever,
And don't forget the joker!'


In fact, no one has ever yet presented a better alternative for filling the brief instant between the cradle and the grave than having 'fun'.

>> i forgat that you humans all go and get anebriated at the weekend.

Well, I dunno about anyone else, but I am going to do some shopping for food, (a minor necesity to the continuance of life), prepare the spare room for some friends (a matter of making them feel welcomed at mine), take them to Stonehenge and Avebury (the former being a place everyone wants to go and the latter being a place everyone should go), and then more of the same tomorrow.

The point being that I will be engaging in pleasurable and meaningful interchanges with other humans.

Oh - and we will probably get inebriated and have fun too. But there you go!

Have a good one GiGs, your way is just not mine. That's all.

B

nice response, ican listen to an argument and understand when its put like that.
few people will actually want all of what i want, but if we can get it togrther, then 'fun' will be all the more readily availible to all, even those outside the system will no doubt recieve massive benefits to a working science community.
in actual fact you may say that im ambitious so you sont have to be. (i dont mean you specific i mean plural)

I think I am merely anbitious in a different way.

I'd prefer to make the life of those around me better in a more immediate, and practical way. And it's practical for *me* because my grasp of science is pretty p*ss poor. In a nuclear power station I'd be Homer Simpson. And I don't think that's a sensible career option for me, or going to further the uman race in any way.

I do have some (minor) talents as an office administrator, and I'm good with people (on the whole). Better for me to use those talents than to try and force me into experimenting in theoretical physics, I think...

And I'm not the only member of the human race like that.

i totaly agree with your point ov view for you.
i do feel though, you mayhaps would feel better doing your job kmowing the profits where to feed world hunger and not some bosses personal exesses.

most people would carry on with their lives as normal.
the only differenc is a higher structure using the result of the normal indaviduals to the best effect rather than the diffusion of money that occours in normal life.
no body need really run it, but as it stands every one has a little slice and can do very little with it.

my first ambition was simply to be competative in business.
then i discovered if you join the right kind of business together, they can provide to each other at cost...folow this long enough and you will automaticaly percieve stage one of my plan wich is to have 49% of every business.
talk about self suficiency.