Monday, March 26, 2012

Overheard in the Hallway:

Roomie is getting ready for work. I notice she is wearing a shirt with what, to my uneducated eye, looks like the result of the unholy coupling of a pinout and a circuit diagram. I am informed it is a tube base diagram. And then some.
RX: "*Lots of electronical terms and assorted wharrrgarbl.*"

Me: "And the cathode is called the cathode because it was discovered growing on bushes in the land of Cathay!"

RX: "No."
How the electrons flow through the teeny copper pipes is a topic on which I am a Subject Matter Moron. I mean, I understand it in the sense that I know that there aren't actually tiny people in my televisions and that closing the switch in the wall does not summon the magic Light Demons, but rather causes electric current to flow through the bulb filament, heating it up and making it glow, but much past that and I'm on pretty unsteady ground.

36 comments:

Robin said...

Given how many real electrical engineers I knew who could do no more than read a parts catalog, they didn't really exceed you much.

Its one of the reasons I get a kick out of Roberta, she seems to actually understand intuitively the stuff she works on. Rarer than you might think.

Bubblehead Les. said...

If you want to really shake up the ol' neurons, ask Bobbie to explain "Hole Flow Theory." And I'm not joking.

Anonymous said...

A girl who wears T-shirts emblazoned with tube base diagrams?

That's uber-cool. At least to this EE who used to design tube radio circuits...

STxRynn said...

When we hit imaginary numbers in calculus, I was a bit shocked. Then we proved they exist is circuits lab. I loved it. Imaginary but verifiable.

bluesun said...

I'm pretty sure the physicists and chemists made up all that stuff anyway.

But then, I'm currently working in Civil Engineering, where all you need to know is how to read numbers off of a table...

eiaftinfo said...

Very cool - few folks even remember tubes, let alone are knowledgable about them. I'm afraid I'm old enough to have acutally worked with them. Built the first stereo in my 7th grade class out of thrown away TVs. How about a shirt photo?

instinct said...

I always assumed when I flipped the switch that the bulb just absorbed the darkness.

Learn something new every day.

Comrade Misfit said...

That's why I didn't become a physicist: I could not wrap my head around how electricity and magnetism worked. Classical mechanics I understood and I could even get a good grip on special relativity. But how all of those `trons did what they did baffled me.

Still does. I just accept that it's PFM and if I touch a powered-up bare wire, the Electrical Demons will punish me for my temerity.

Sebastian said...

How electricity moves through a conductor is more physics than Electrical Engineering. Engineers spend more time understanding the properties of electricity moving through conductors than the mechanism of such.

CE Patrick said...

I have a firm belief in the tiny light demons.

Sebastian said...

There are tiny light demons. But they are called electrons :)

Brad K. said...

Ben Franklin established the standards of direct current electricity. He posited that electricity moved from the "positive" to "negative" poles. We stamp our batteries that way today.

Then those annoying physicists noticed that electrons flow when electricity does. But they move from the more-negative place to the more-positive end of the wire (or path of ionized air, or across any mundane conductor). It is the "place" that the electron "was" that moves from positive to negative.

Ole Ben got his plus and minus signs crossed, because he didn't know that electricity is a flow of electrons, which by his labels are "negative".

Cathode is named the cathode because it isn't the anode ("not" node, or place where electricity goes from). I forget whether it is the electrons or the electricity (electron holes) that flow from the cathode, especially in Cathode Ray (display) Tubes (CRT).

Then there are the semiconductors, chunks of sand (gravel won't do) with guck spilled on it, so electrons (or holes, one) moves one way but not another, and can change sometimes if you hook a battery (extra elecrons/holes) up to a nearby control or trigger chunk of gucked sand. They call one color of guck 'P' and another color 'N', so you get PN junctions, and NPN or PNP transistors. (resistors that sometimes let electricity flow across -- transit --).

Now, why some of the cylinders in the truck fire sometimes, and others fire all the time, that seems just, well, rude.

Scott said...

Good for Roberta. We just tolerate the rest of you until we get caught up and have time to take over the world.

By the way, I love tubes and one day I will make myself a shortwave with all of the tubes that I have in my garage. Hopefully before TEOTWAWKI.

Loki1776 said...

@instinct, you were right and common "wisdom" is wrong. What people call light bulbs are really dark suckers.

freddyboomboom said...

One of the first "multimeters" I used when training to be an Aviation Electronics Technician for Uncle Sam's Big Grey Canoe Club in 1985 was a Vacuum Tube Volt Ohm Meter with a Nixie tube display.

Ah, the good old days... :)

Anonymous said...

Two comments:
a) to Bluesun--remember, Aero/Mech/Chem/Elec-Engineers build weapons systems", CEs build "targets". :-)

b) "Any sufficiently advanced technology is indistinguishable from magic."

WV: overotin onallemb--I propose that Sir Terry P. uses the WV captcha generator for names in the next Discworld book.

Anonymous said...

John Ringo said it in one of the Troy books (paraphrase):

"Back up, Doc, to me, 'electricity' is French for 'Don't f*ck with it'."

I not only believe in the Light Demons and the Magic Elves that live behind my laptop screen, if the electirc company told meI had to clap my hands together to keep them working, I'd sound like Oscar night. . . [chuckle]

AuricTech said...

I not only believe in the Light Demons and the Magic Elves that live behind my laptop screen, if the electirc company told meI had to clap my hands together to keep them working, I'd sound like Oscar night

Well, they say that "many hands make light work".... ;-)

Stuart the Viking said...

I did aviation electronics in the US Marines. Hole flow is easy to understand if you don't think too hard about it, problem is, most people DO think too hard about it.

It's Gravity that I think they are all lying about. I feel more "pushed down" by all that atmosphere above me than "pulled down" by the earth. I mean get real. Like something magically has a magnetic pull just because it is super big? If that was the case, I would fly right off because I am not made of metal! But NO, all you suckers believe! fools...

s

Don M said...

If I may be so bold, could you post a picture of the shirt?

With or without roomie...

Critter said...

is electricity that stuff in the walls that hurts when i stick my tongue in those little holes?

secret code: sedervie kesess: new character in a David Weber novel.

Canthros said...

Dad's got a EE degree with a specialization in power generation. He repairs tube radios for fun in his free time.

Mom's got a ChemE degree. She worked for the local plunder and loot^Wpower and light until retirement.

As for me, I changed degree programs from Computer Engineering to Computer Science when it became very clear, very early, that I was having some serious difficulty hacking circuits.

So, I feel your pain, Tam. Most of the time, when my Dad starts talking about that stuff, my brain just glazes right over.

Scott Gelber said...

As a EE who got tapped to teach EMI to other EEs, one should see eyes glaze over when simple field theory and its results are discussed.

"What do you mean when you suggest moving the wire harness away from the other harness that is switching the 1200W load?"

rickn8or said...

Those of us that work / play with this electronical stuff forget that not everybody understands the magick.

If you really want to give yourself a headache, ask Roberta how a dead short between two wires of a transmission line isn't. And if you put a bunch of them side-by-side, you eventually wind up with a square pipe that channels RF energy.

Roberta X said...

Aw, heck, transmission-line theory is almost *easy.* I've got an ooooooolllld NAB Engineering Handbook with an article by some RCA engineers that gets the reader up to speed on open-wire line, fast, then spins it into coax and waveguide, resonant cavities and reactive line segments and by the end, you'd swear you knew how that stuff works -- with algebra and high-grad chalk talk. I'd like to scan it in and post it on the Teh Innernet but they'd probably sue me into the middle of next week.

Roberta X said...

(I should point out that my understanding of circuit functioning is based in part -- sometimes in large part -- on mental images that owe a lot to the old Warner Brother animators and various radio-magazine cartoonists for the 1930s and '40s. Electrons roll and bounce like roller-coaster cars; tubes strain and heave at currents like sailors hauling a line; resonant circuits toll like bells.)

T-shirt, here: http://www.tubesandmore.com/cemirror/inv/G-853.GIF

Jerry said...

OOOOhhhh, I loves me some tubes. EL-34s for my wild side, 6L6s for the chime and jangle. Oh yeah, capcha can bite me.

Zendo Deb said...

filaments? There are no filaments in your compact florescent bulbs. That's plasma doing the glowing.

(Think of a fluorescent as a tiny plasma conduit from Star Trek. Or something.)

KC said...

Roberta, do you know if the shirt is of any particular tube? It looks like some sort of dual triode to me, but my tube experience is limited to the 4CX250B to 3CX20,000A7 size class, working on FM transmitters at least a decade older than I am.

Roberta X said...

KC, I'm pretty sure it's an EIA 9A base, the 12AX7/12AT7 family of "miniature" dual triodes, not too uncommon in audio amplifier service.

It's no '19 or 6SN7, mind you...

Tim D said...

If cathodes are from Cathay I really don't want to know where they pulled the anodes from.

-Tim D

Larry said...

It's all magic smoke and mirrors. Let the magic smoke out and it doesn't work any more. FM means F'n Magic.

I learned all of this in Navy avionics school. And to tell you what kind of a nerd I am...I intuitively grokked hole flow theory as soon as it was described to me.

mikee said...

My Quantum Chemistry Professor described quite thoroughly using Math the way electrons tunnel through thin layers of insulating oxides. Then he walked over to the light switch and turned the classroom lights on and off several times.

Then he said that although he understood the math, and from a scientific perspective it made sense, it still "freaked him out a little bit every time he hit the switch."

Inspector said...

You have an asterisk, indicating a footnote, but there is no footnote.

[twitch]

Inspector said...

Nevermind. Stupid eyeballs.

Windy Wilson said...

Hey, the Vacuum Tube Volt Meter, the big, heavy, clunky, Vit Vim!
The size of my color printer, and comparable in weight, today's equivalent fits in my pocket and cost under $20.

"mental images that owe a lot to the old Warner Brother animators and various radio-magazine cartoonists for the 1930s and '40s. Electrons roll and bounce like roller-coaster cars; tubes strain and heave at currents like sailors hauling a line; resonant circuits toll like bells."

I weep, because if the idiot incipient administrator who was my electronics teacher in high school had thought to use those, I might be an engineer today. I understand electron flow, and even diodes and resistors, but Transistors were beyond me, so I went off to history. :-(