Newbies to electronics and lighting...a rough analogy

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quantumplasmathingie
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Joined: Sat Jun 23, 2007 4:19 pm

Newbies to electronics and lighting...a rough analogy

Post by quantumplasmathingie »

I'm new to this whole LED thing myself...I just got started messing around with lighting a few months ago, but I've already done a couple of fun builds for my nephew on internal batteries for him to play with.
I have to admit, I was pretty confused at first with all these electronic terms and numbers and units...these things don't always behave the way you'd think they should.

I was thinking about it (after a couple of beers, so my mind was nice and relaxed), and it occurred to me that electricity in a circuit is analogous to water flowing from a tank (like a tank on a water tower) through a series of pipes. The voltage is the water pressure, the current is amount of water flowing through a given pipe, and the resistance is like the diameter of the pipe. A large pipe (wide gauge wire) has lower resistance (more flow-through), and a narrower pipe (narrow gauge wire) has a higher resistance (less flow-through). Resistors are like reduction valves or joins, reducing a larger diameter pipe to a smaller diameter...decreasing the amount of flow through the pipe.

You can imagine my suprise when I discovered that the Hydraulic Analogy (as it is called), has been around for over a century, and was called the Drain Pipe Theory by Oliver Heaviside (a pioneer in electrodynamics). There's a whole Wikipedia page on it: http://en.wikipedia.org/wiki/Hydraulic_analogy

There are limits to the analogy, of course. but in designing a simple circuit to light some LEDs, it works well to help figure out how to provide enough current, without draining your battery too quickly.
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jcdenton
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Post by jcdenton »

Yeah, electricity is like water, the only real difference is, that if you drill a hole into a wall and hit a water-pipe, water comes flowing out. Hit a wire and... ;) gotta hate those electrons floating around the room ;)

But I'm glad you're getting the hang of it. I'm fairly new to all the soldering and LED business and I'm learning a great deal as I'm going as well.

Cheers
JC
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Post by Sparky »

The fun thing is when someone realizes that all the disciplines, from mechanical engineering, to physics. Use the same basic equations, just with different Greek letters. It dawned on us as we sat in the mandatory upper division physics class that the equation they were showing was the same we were learning for resistor, capacitor, inductor circuits. And when we took the mandatory mechanical engineering class, the same equation was used in calculating the strut and spring for a suspension system.


In a wire as it heats its resistance rises, the more resistance there is the more power it consumes creating heat. In a semiconductor as it heats its resistance decreases, also known as thermal runaway. In both cases the heat causes the base problem to escalate until the smoke comes out of the part and it stops working, with semiconductors it usually happens quickly. In wires a circuit breaker or other component limits the amount of power the wire gets so it can't 'runaway.'
<a href="http://www.kc6sye.com/2_wheresaneatpart.jpg" target="_Sparky">Is this plastic thingy on the counter a neat part?</a> <a href="http://www.kc6sye.com/1_casting_inprogress.jpg" target="_Sparky">Let's cast it.</a>
quantumplasmathingie
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Joined: Sat Jun 23, 2007 4:19 pm

Post by quantumplasmathingie »

Oh yeah, I'm really groovin' on the flashy lights! I've been building models for a long time, but always balked when it came to lighting them up...which I'm kicking myself for not starting into sooner.

Electronics is an entirely new fascinating hobby unto itself, and since I've already invested time and some dough into testing equipment and such, I can only see myself delving deeper into it as time goes by. Since I've got a 5-year-old nephew who's imagination completely transcends into other dimensions, my imagination is firing up to build him cooler gadgets and crazier models!

It's all thanks to you guys (especially Mr. Zog and Sparky). You've shown me how easy it is to jump right into this new sea of information and start paddling! Much obliged!
Madman Lighting
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Post by Madman Lighting »

Welcome to the joy of blinky lights! I got started with model train wiring and radio shack starter kits. Now I do it for a living and the Hydraulic Analogy still hold true for lots of stuff. Welcome and enjoy!

-JC.
That Madman Who Lit Up Deep Space Nine
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