Let there be light

[Hero999]

I just assumed that LED rope lighting had the resistors already built-in.

If what you are saying is true then why do we bother with series resistors?

I've done experiments involving LEDs and constant voltage supplies and the current seems to change very widely, within 100mV an LED's current can go from 10mA to 30mA and this can vary between different LEDs of the same type.

 

[things]

The worst i have one is wired 1 LED up to 55kv dc

 

[Hero999]

Anothing thing about LEDs is their forward voltage drops with increasing temperature which can cause thermal runaway.

The only way to safely run an LED without a series resistor is to use a supply with a voltage just on the trun on voltage so it doesn't get warm enough for it to happen.

 

[Marks256]

I wish i would have been around during the core of the computer revolution. Aaaah... Oh well, at least we will all get to see microsoft go down the tubes...

I am a bit rusty on my computer history. Wasn't it konrad zuse that made the first fully functioning computer in '41?

I think it would be fun to build a relay computer. All that clicking and whatnot. Aaah... What would they need for a power source? I am guessing it would be quite high!

 

[Sceadwian]

You'd have to define computer Marks. An abacus is a fully functioning mechanical computer. The first 'dust abacus' date to around 3000BC or so. It depends on your level of abstraction.

 

[mvs sarma]

The worst i have one is wired 1 LED up to 55kv dc

ASTONISHING. How did you manage to get the requied mA current??

 

[mvs sarma]

I am not old. (62)
I am just not as young as I used to be.
I feel almost the same as when I was young.
Some old people act and feel very old.

In some parts of world it became a habit to say " I am 62 years old."
one of my Officers used a phrase "I am xx years young."

 

[audioguru]

"I am xx years young."

What is the age when you change from saying how old you are to saying how young you are???

 

[Nigel Goodwin]

What is the age when you change from saying how old you are to saying how young you are???

If you have to ask, you've not reached it yet!

 

[audioguru]

Many women stay at age 39 for 10 or 20 years.

 

[Nigel Goodwin]

Many women stay at age 39 for 10 or 20 years.

And at 29 for 10 or 20 years before that!

 

[3v0]

You'd have to define computer Marks. An abacus is a fully functioning mechanical computer. The first 'dust abacus' date to around 3000BC or so. It depends on your level of abstraction.

If you start digging I think you will find that the abacus is grouped with calculators.

Prior to the industrial revolution there were quite a few advancments made in machanical calculators. But they were expensive to produce and only a few were produced for the well to do.

During the industrial revolution many of these designs were produced by factories.


History of Mechanical Calculators - Part I

 

[3v0]

I wish i would have been around during the core of the computer revolution.

**broken link removed**

In the days of the Z80 it took about 50 square inches of PCB to do what a PIC can do in 2 or less. It cost buckets more money to make that board.

The raw computing power you have at your finger tips is astounding. The things you can make happen on a few square inches of PCB is mind boggling.

It is up to you (all of us actualy) to get your butt moving and do somthing useful with all these tools.

Aaaah... Oh well, at least we will all get to see microsoft go down the tubes...

I never though I would be defending Microsoft but:
I do not care for the way Microsoft does buisness.
I like fact that it provides quite a few decent paying CS jobs, pays taxes, and pulls some money back into the US.

What would we gain if it went away.
I am thinking not nearly so much as we would loose.

 

[HiTech]

Way back in early elementary school I used an abacus in class.

**broken link removed**


A couple of years later I used a Magic Calculator and thought I was a real cool dude with it!

**broken link removed**

Following that I used a slide rule:

**broken link removed**

Then onto a scientific, programmable HP caculator:

**broken link removed**

... and from there, a garden variety of basic function caculators.

As I have aged it's good to exercise the mind often so now I use this:

**broken link removed**

 

[Marks256]

It is up to you (all of us actualy) to get your butt moving and do somthing useful with all these tools.

i still think the Z80 was and still is divine... WORSHIP THE Z80!!!!!!!