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Re: CPU <> Memory chip communication interface

 
 
Skybuck Flying
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      08-05-2005
Nice introduction to signals across a wire.

http://penguin.dcs.bbk.ac.uk/academi...nous/index.php

I never understood the difference between voltage and ampere... to bad this
page doesn't discuss how ampere is related to voltage. (voltage<->ampere
very confusing )

One thing I do understand now. The higher the voltage the higher the one
(or maybe is ampere at work here as well ? )

Another surprising things is +voltage is zero and -voltage is one. I
would have done it the other way around... 1 is closer to positive so
+voltage is 1 and -voltage is closer to zero so -voltage is 0.

Bye,
Skybuck.


 
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Pooh Bear
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      08-05-2005

Skybuck Flying wrote:

> Nice introduction to signals across a wire.
>
> http://penguin.dcs.bbk.ac.uk/academi...nous/index.php
>
> I never understood the difference between voltage and ampere... to bad this
> page doesn't discuss how ampere is related to voltage. (voltage<->ampere
> very confusing )


That's pretty fundamental. The classic example is to compare electricity to water.

Voltage is like water pressure - current is like water flow. With no pressure no water
flows. The larger the pipe ( less resistance to flow ) the more water flows. In a similar
way, the less electrical resistance, the more Amps flow in a circuit for a given voltage.

Reduce the pressure ( Volts ) and the flow ( current ) will reduce likewise.

You sound interested in electronics. An admirable interest.

Why not do what I did when young and simply do some self-study ? Books can be good you
know ! Maybe today's way of living tends to overlook this obvious source of excellent
info ?

Now - please stop trolling here.

http://en.wikipedia.org/wiki/Usenet_troll


Graham

 
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Skybuck Flying
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      08-05-2005

"Pooh Bear" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> Skybuck Flying wrote:
>
> > Nice introduction to signals across a wire.
> >
> >

http://penguin.dcs.bbk.ac.uk/academi...nous/index.php
> >
> > I never understood the difference between voltage and ampere... to bad

this
> > page doesn't discuss how ampere is related to voltage. (voltage<->ampere
> > very confusing )

>
> That's pretty fundamental. The classic example is to compare electricity

to water.
>
> Voltage is like water pressure - current is like water flow. With no

pressure no water
> flows. The larger the pipe ( less resistance to flow ) the more water

flows. In a similar
> way, the less electrical resistance, the more Amps flow in a circuit for a

given voltage.

Does this mean a pipe diameter (of a certain material) always allows a
certain maximum voltage ?

So if the source of the voltage becomes to high the pipe blows ?

Probably yes, ok that's easy.

Now what about two different pipes:

Pipe A has a large diameter with a maximum of 100 volts to flow through it.

Pipe B has a small diameter with a maximum of 15 volts to flow through it.

Source A has a pressure of 14 volts and is connected to pipe A.

Source B has a pressure of 14 volts and is connected to pipe B.

I have two meters.

I stick a voltmeter A in pipe A.... what would it measure ?

I stick a voltmeter B in pipe B... what would it measure ?

Both would probably measure 14 volts.

The difference would be the ampere.

The flow through pipe B would have to be faster, since it's smaller.

The flow through pipe A could be slower, since it's wider.

According to your explanation:

Sticking an ampere meter in pipe A should show a lower ampere.

Sticking an ampere meter in pipe B should show a higher ampere.

If this is how it works I think I understand it a little bit

However microelectronics are very very very small.

So for me it's hard to see the diameter and the resistance... (resistance is
related to the material )

Ok I think I am starting to get it.

Let's see even a more complex example:

Pipe A is split up into

Pipe A1 with a diameter of allowing 5 volts

Pipe A2 with a diameter of allowing 95 volts.

Now a good question is the following:

The voltage at pipe A1 would be 5 volts ? or would it blow up ?

It could be possible that the remaing 9 volts would simply go into pipe
A2...

It probably depends on the strength of pipe A1...

At this point I really wouldn't know what the answer is

Maybe it's related to the resistance or something... if it could resists 15
volts it might survive...
But I don't think this is what resistance means ? or maybe it does ?

I thought resistance means how much voltage is lost....

Maybe this is the correct answer after all... if Pipe A1 has a resistance of
9 volts it could allow 5 volts to flow through it...

But what would happen to the other 9 volts ?

Would it go lost in Pipe A1 or would it flow through Pipe A2 without loss ?

I dont think the voltage would be simply halfed... since that's not how
water behaves

So the point is: The concepts pressure, flow, maybe even resistance are easy
to understand... but how it behaves in reality especially in electronics is
a little bit more difficult to understand

Unless the answers are really simple... so I am curious what the answer(s)
would be Especially the splitting up of the pipe question

Bye,
Skybuck.


 
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Pooh Bear
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      08-05-2005

Skybuck Flying wrote:

> "Pooh Bear" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> >
> > Skybuck Flying wrote:
> >
> > > Nice introduction to signals across a wire.
> > >
> > >

> http://penguin.dcs.bbk.ac.uk/academi...nous/index.php
> > >
> > > I never understood the difference between voltage and ampere... to bad

> this
> > > page doesn't discuss how ampere is related to voltage. (voltage<->ampere
> > > very confusing )

> >
> > That's pretty fundamental. The classic example is to compare electricity

> to water.
> >
> > Voltage is like water pressure - current is like water flow. With no

> pressure no water
> > flows. The larger the pipe ( less resistance to flow ) the more water

> flows. In a similar
> > way, the less electrical resistance, the more Amps flow in a circuit for a

> given voltage.
>
> Does this mean a pipe diameter (of a certain material) always allows a
> certain maximum voltage ?
>
> So if the source of the voltage becomes to high the pipe blows ?


That would be exceptional and irrelevant to any sensible understanding.

I'm getting bored of your trolling now.....

Graham

 
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Skybuck Flying
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Posts: n/a
 
      08-05-2005

"Pooh Bear" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> Skybuck Flying wrote:
>
> > "Pooh Bear" <(E-Mail Removed)> wrote in message
> > news:(E-Mail Removed)...
> > >
> > > Skybuck Flying wrote:
> > >
> > > > Nice introduction to signals across a wire.
> > > >
> > > >

> >

http://penguin.dcs.bbk.ac.uk/academi...nous/index.php
> > > >
> > > > I never understood the difference between voltage and ampere... to

bad
> > this
> > > > page doesn't discuss how ampere is related to voltage.

(voltage<->ampere
> > > > very confusing )
> > >
> > > That's pretty fundamental. The classic example is to compare

electricity
> > to water.
> > >
> > > Voltage is like water pressure - current is like water flow. With no

> > pressure no water
> > > flows. The larger the pipe ( less resistance to flow ) the more water

> > flows. In a similar
> > > way, the less electrical resistance, the more Amps flow in a circuit

for a
> > given voltage.
> >
> > Does this mean a pipe diameter (of a certain material) always allows a
> > certain maximum voltage ?
> >
> > So if the source of the voltage becomes to high the pipe blows ?

>
> That would be exceptional and irrelevant to any sensible understanding.
>
> I'm getting bored of your trolling now.....


I am not trolling I am trying to understand it. But ok I can see how a dirty
mind might think that's funny.

And in case you didn't understand that sentence here it is again:

So if the pressure of source of the voltage becomes to high the pipe blows ?

Without the smiley

Bye,
Skybuck.


 
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Pooh Bear
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      08-05-2005

Skybuck Flying wrote:

> "Pooh Bear" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> >
> > I'm getting bored of your trolling now.....

>
> I am not trolling I am trying to understand it. But ok I can see how a dirty
> mind might think that's funny.


Your amusement factor is declining fast.

I suggest ( if you're serious ) that you start reading a few decent books on electronic
theory and practice. It'll come in handy !

Ohhh... hobby magazines such as Elektor ( if it still exists ) are a good source of info
about practical circuits that can be easily built on a hobbyist basis. They are good
foundations upon which to learn.

Graham

 
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