0730: "Circuit Diagram"

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Kirby
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Re: "Circuit Diagram" Discussion

Postby Kirby » Thu Apr 22, 2010 12:53 pm UTC

jslegers wrote:...So, I too confirmed the resistor blob value of 25265/33783 ohms using MATLAB symbolics and a reduced admittance-matrix [Zeq = (Ynn - (Ynr Yrr^-1 Yrn))^-1]. As mentioned above, this rounds to ~0.7479 ohms. And, while I appreciate the sentiment, It can only be ROUNDED to 1.337 mhos, and that likely happened by accident. Also, I now have an unmitigated desire to form a band called L337 Mhos.

You would likely not be interested to know that, for 5% normally-distributed resistors, this equivalent resistance would be ~ 0.7479 +- 0.0065 ohms. For 1% resistors, it would be +-0.0013 ohms. This comes from simulation in MATLAB.

Just thought I'd weigh in.


You wanna try building a circuit out of 1-ohm resistors that perfectly yields 1.337 mhos, huh?

Joking. Whether accidental or not, I'm impressed.

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glitterbug12
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Re: "Circuit Diagram" Discussion

Postby glitterbug12 » Thu Apr 22, 2010 2:03 pm UTC

This amuses me... reminds me of this piece.

jtlk
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Re: "Circuit Diagram" Discussion

Postby jtlk » Thu Apr 22, 2010 3:04 pm UTC

A few people have mentioned the flip-flop/sandal; it's also the latch for the holding pen...

z-bot
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Re: "Circuit Diagram" Discussion

Postby z-bot » Thu Apr 22, 2010 6:26 pm UTC

andrewxc wrote:Does anyone know what the connections are in the bottom-left corner?
It looks like something out of The Phantom Tollbooth.


The bottom left looks like a human head/brain. The wire that leaves it to the right turns into something that looks like an EEG.

The Arduino diss is very cool. Heck, just get an Atmel µC and hack a cheapo programmer yourself.

beavinator
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Re: "Circuit Diagram" Discussion

Postby beavinator » Thu Apr 22, 2010 6:59 pm UTC

Is it just me, or does the lower-left section strongly resemble a map of the "maze of twisty little passages, all alike" from Zork I...?

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Re: "Circuit Diagram" Discussion

Postby bmonk » Thu Apr 22, 2010 8:45 pm UTC

joplju wrote:Um... I hate to be a nit-pick, but I'm going to add my own brand of nerdiness to the mix here...

That warm front isn't a warm front. That's actually the symbol for a dry line.

I was just surprised it wasn't an occluded front. Would a warm front really produce the desired effect?

And the fact that the batteries are wired in reverse doesn't really matter, since the 50v battery is grounded on both sides.

Finally, does the holy water have to be the old recipe, with added salt, or is the modern version acceptable?
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PurdueSi2
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Re: "Circuit Diagram" Discussion

Postby PurdueSi2 » Thu Apr 22, 2010 9:33 pm UTC

Hilarious that he references EE 201. I'm sure it's the common circuit analysis course, but it's dead on for Purdue. I lol'd when I read that.

Overall this is probably the comic I've enjoyed most, all-time, and I've read them all. I've printed it on 11x17 and hung it in my cube at work.

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Nyerguds
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Re: "Circuit Diagram" Discussion

Postby Nyerguds » Thu Apr 22, 2010 10:26 pm UTC

Haha, wow. The more I analysed the diagram, the harder I laughed... there's just sooo many jokes and references in there.

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phillipsjk
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Re: "Circuit Diagram" Discussion

Postby phillipsjk » Thu Apr 22, 2010 11:17 pm UTC

I noticed the floor of the stadium is just below ground (ground is positive in that case).
Did you get the number on that truck?

FearfulFerret
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Re: "Circuit Diagram" Discussion

Postby FearfulFerret » Fri Apr 23, 2010 12:09 am UTC

Well, the class itself is ECE220 here, but all the same...

I am this --||-- close to firing up PSpice and testing the equivalent resistance of that bundle, though I see that's already been done.

mlerei
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Re: "Circuit Diagram" Discussion

Postby mlerei » Fri Apr 23, 2010 12:23 am UTC

I just spent all day looking at Mitsubishi PLC code (old and not incredibly user friendly) with all the descriptions (if even present) for the contacts in Japanese, which I can't read. It makes me feel so much better to see a circuit with proper labeling.

drevil_999
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Re: "Circuit Diagram" Discussion

Postby drevil_999 » Fri Apr 23, 2010 1:25 am UTC

It is the schematic for a retro encabulator.

http://www.youtube.com/watch?v=RXJKdh1KZ0w

joplju
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Re: "Circuit Diagram" Discussion

Postby joplju » Fri Apr 23, 2010 3:48 am UTC

bmonk wrote:
joplju wrote:Um... I hate to be a nit-pick, but I'm going to add my own brand of nerdiness to the mix here...

That warm front isn't a warm front. That's actually the symbol for a dry line.

I was just surprised it wasn't an occluded front. Would a warm front really produce the desired effect?


Well, it depends on the effect Randal was going for. All I know is that, for an occluded front, the barbs (points) and pips (circles) are on opposite sides of the front (considering the occlusion is the warm front riding over the top of the cold front). On a warm front, the pips are facing the same way (generally North, in the northern hemisphere, more specifically the eastern US). They are, however, spaced apart. Dry lines, on the other hand (most commonly seen during the summer in west Texas), have pips on the leading edge (East) that are closely spaced, as Randal has drawn.

Congratulations, you now know more than you ever wanted to about weather maps!

DHeadshot
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Re: "Circuit Diagram" Discussion

Postby DHeadshot » Fri Apr 23, 2010 7:27 am UTC

I'm working on building this in Crocodile clips...

Major Bummer
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Re: "Circuit Diagram" Discussion

Postby Major Bummer » Fri Apr 23, 2010 9:32 am UTC

Bottom left

You are in a twisty maze of passages, all alike.

Geekoid
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Re: "Circuit Diagram" Discussion

Postby Geekoid » Fri Apr 23, 2010 3:14 pm UTC

GunJack wrote:pretty sure that Randall posted this, sat back with a chronometer, and counted the time to see the first post trying to resolve this...maybe there's a poll... some betting.... yeah...
and the "one mile=one kilometer" joke is for THOSE COUNTRIES that still uses miles...


Don't tell me you are one of THOSE COUNTRIES that pours beer into a pint glass.

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Re: "Circuit Diagram" Discussion

Postby Geekoid » Fri Apr 23, 2010 3:21 pm UTC

dwasifar wrote:
monkeyman8 wrote:I had to look up that brown blue orange = 16K resistance, I feel shamed :(


I didn't, and it's due to a pungent mnemonic taught to me and the rest of my Basic Electronics class when I was a high school freshman.

0 - Bad (black)
1 - Boys (brown)
2 - Rape (red)
3 - Our (orange)
4 - Young (yellow)
5 - Girls (green)
6 - But (blue)
7 - Violet (violet, duh)
8 - Gives (gray)
9 - Willingly (white)

That should give you an idea of how long ago I went to high school. A public school teacher offering this mnemonic today would be flayed alive. But, for better or worse, it did stick with me, and as far as I know, Mr. Gene Spratt retired with his skin still attached.



10 - Good (gold)
11 - Sex (silver)
12 - No Charge

Yeah, I got my degree a long time ago.

Funny how many people don't get the title of this comic. I don't think he meant to to just be taken as an electrical circuit.

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phillipsjk
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Re: "Circuit Diagram" Discussion

Postby phillipsjk » Fri Apr 23, 2010 4:37 pm UTC

I learned a Basically Decent version:
0 - Bad (black)
1 - Boys (brown)
2 - Race (red)
3 - Our (orange)
4 - Young (yellow)
5 - Girls (green)
6 - But (blue)
7 - Violet (violet, duh)
8 - Generally (gray)
9 - Wins (white)

I was shocked! the first time I heard the violent version.

I suppose "Black" == "bad" => Racist :P
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neodorian
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Re: "Circuit Diagram" Discussion

Postby neodorian » Fri Apr 23, 2010 5:21 pm UTC

beavinator wrote:Is it just me, or does the lower-left section strongly resemble a map of the "maze of twisty little passages, all alike" from Zork I...?


Came here to see if anyone else saw that. That is the first thing I notice and it makes me cringe a little. That maze was a PITA until I got Invisiclues.

forrestv
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Re: "Circuit Diagram" Discussion

Postby forrestv » Sat Apr 24, 2010 4:32 am UTC

Image
http://im.forre.st/resistors.jpg

I got 347 ohms for that circuit made of 463 ohm resistors, so 347/463 or about 0.749 ohms.

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Re: "Circuit Diagram" Discussion

Postby modularblues » Sat Apr 24, 2010 8:12 am UTC

I almost puked when I saw this. I'm EE.

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Re: "Circuit Diagram" Discussion

Postby Mikeski » Sat Apr 24, 2010 11:02 am UTC

Re: color codes

My high school electronics class learned two versions: **triggery misogyny not found**, bad beer rots our young guts but vodka goes well. Both with 'get some now' for the tolerance bands.

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5th Earth
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Re: "Circuit Diagram" Discussion

Postby 5th Earth » Sun Apr 25, 2010 12:12 am UTC

I surprised no one has said anything about the light absorbing diode.

Also, out of curiosity, what would people peg as the "most expensive chip available"?
It seemed like a good idea at the time.

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Raptortech97
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Re: "Circuit Diagram" Discussion

Postby Raptortech97 » Sun Apr 25, 2010 12:43 am UTC

5th Earth wrote:Also, out of curiosity, what would people peg as the "most expensive chip available"?

It would have to have at least one Heisenberg Compensator, an area for cohering quantum computing, wireless entanglement, and the processing power of several Crays combined. It could be no larger than one square centimeter.
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phillipsjk
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Re: "Circuit Diagram" Discussion

Postby phillipsjk » Sun Apr 25, 2010 3:35 am UTC

5th Earth wrote:I surprised no one has said anything about the light absorbing diode.


That is a real component.

Wikipedia also has a page.
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ZippoLag
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Re: "Circuit Diagram" Discussion

Postby ZippoLag » Sun Apr 25, 2010 6:23 am UTC

forrestv wrote:Image
http://im.forre.st/resistors.jpg

I got 347 ohms for that circuit made of 463 ohm resistors, so 347/463 or about 0.749 ohms.


I think I should use this approach on my next EE test rather than calculating stuff :P

btw, seriously, I want a poster of this comic.
I WANT IT NOW

merseyless
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Re: "Circuit Diagram" Discussion

Postby merseyless » Sun Apr 25, 2010 7:37 am UTC

drevil_999 wrote:It is the schematic for a retro encabulator.

http://www.youtube.com/watch?v=RXJKdh1KZ0w


can't be, it's not surmounted by a malleable logarithmic casing mounted on a base-plate of prefambulated amulite...
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Re: "Circuit Diagram" Discussion

Postby 1055 » Sun Apr 25, 2010 9:38 am UTC

I almost hope this doesn't become a poster, because I can imagine it taking a significant toll on my productivity. Even worse would be a mousepad.

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I love this

Postby foppit_poo » Mon Apr 26, 2010 8:05 am UTC

I'm an electrician working as a service technician in the lift industry. It's a horrible industry for keeping those essential diagrams in good, readable condition. Oil leaks from gearboxes. Sunlight fades them to nothing. Roofs leak on them. They get folded so often they tear. Motor-room-less lifts aren't much better - I've found them stuffed on top of fuse & rectifier boards.

With acknowledgement of course - I plan to print out a few to replace some of the many missing diagrams. :D Sometimes if you didn't laugh, you'd cry for sure.
Last edited by foppit_poo on Mon Apr 26, 2010 8:58 am UTC, edited 1 time in total.

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Re: "Circuit Diagram" Discussion

Postby domino14 » Mon Apr 26, 2010 8:19 am UTC

I was an anti-Arduino snob, mainly because it makes everything too easy, but I actually had to use one recently because it would have taken too long to design and build the circuit the way I wanted it, and it was just for a quick prototype. I was very impressed by the shields, the programming language and the overall ease of use. Don't be an Arduino snob if you are one. Besides, they can be re-flashed easily and then it's just an AVR with a cool board and lots of functionality.

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Re: "Circuit Diagram" Discussion

Postby mike150160 » Mon Apr 26, 2010 8:21 am UTC

Major Bummer wrote:Bottom left

You are in a twisty maze of passages, all alike.



I thought it was a game of sprouts

lbarton
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Re: "Circuit Diagram" Discussion

Postby lbarton » Mon Apr 26, 2010 3:02 pm UTC

Love it,

Reminds me of the electrical engineers at my last place. It'd be funny except that we'd already told the customer we'd fixed it 2 weeks ago and we were sure it'd work no probs :roll:

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Re: "Circuit Diagram" Discussion

Postby hthall » Tue Apr 27, 2010 5:34 am UTC

Kirby wrote:
jslegers wrote:...So, I too confirmed the resistor blob value of 25265/33783 ohms using MATLAB symbolics and a reduced admittance-matrix [Zeq = (Ynn - (Ynr Yrr^-1 Yrn))^-1]. As mentioned above, this rounds to ~0.7479 ohms. And, while I appreciate the sentiment, It can only be ROUNDED to 1.337 mhos, and that likely happened by accident. Also, I now have an unmitigated desire to form a band called L337 Mhos.

You would likely not be interested to know that, for 5% normally-distributed resistors, this equivalent resistance would be ~ 0.7479 +- 0.0065 ohms. For 1% resistors, it would be +-0.0013 ohms. This comes from simulation in MATLAB.

Just thought I'd weigh in.


You wanna try building a circuit out of 1-ohm resistors that perfectly yields 1.337 mhos, huh?

Joking. Whether accidental or not, I'm impressed.


Well, there's a trivial way to build a 1337 mho circuit using exactly 1337 perfect 1-ohm resistors (and perfectly conducting wires), so it follows that there is an easy (if cumbersome) way to build a circuit of exactly 1.337 mhos using a total of 1,337,000 of them. A little further thought produces a 7331-resistor circuit, but that's still far from ideal--invoking some number theory you can get down to 575 resistors, and that's still not going beyond series-parallel networks, let alone beyond planar. It's an interesting question in general: given a particular positive rational number x, what is the minimum number of perfect 1-ohm resistors required to make a circuit of exactly x mhos?
Look at me, still talking when there's Science to do.

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phillipsjk
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Re: "Circuit Diagram" Discussion

Postby phillipsjk » Thu Apr 29, 2010 2:43 am UTC

You lost me at "invoking some number theory you can get down to 575 resistors."

If you want to get 1.337 milliOhms from as few 1% 1 Ohm resistors as possible, you can't do better than putting them all in parallel.

1/0.001337=747.94
With 3 significant digits, 748 resistors in parallel would be within the tolerance of the resistors.

Do you know of some magical way of wiring resistors that is not a series-parallel circuit?

Edit proof:

Premises
  1. A resistor network is made up of series-parallel circuits
  2. Series: Rtotal=R1+R2+R3+...+Rn
  3. Parallel: Rtotal=(1)/((1/R1)+(1/R2)+(1/R3)+...+(1/Rn))
  4. Resistor networks can be broken into sub-networks

Our goal is to lower the resistance an arbitrary amount with as few resistors as possible.

Claim: The resistor network of the chosen resistance with the fewest resistors will have no resistors in series iff extra accuracy is not needed.

  1. The smallest possible resistor network is a single resistor. (by 1 and 4)
  2. Resistor networks in series always raise the resistance. (by 2 and A)
  3. Resistor networks in parallel always lower the resistance. (by 3 and A)
  4. The simplest resistor network is formed with a single resistor. (by A)
  5. To lower the resistance, extra resistors must be added in parallel. (by 1, B and C)
  6. Recursively add a single resistor in parallel until desired resistance is overshot or met. (until resistance <= target resistance)
  7. At the end of recursion we have the simplest possible resistor network with the desired resistance. (By D, E and F)
  8. The simplest possible resistor network with the desired resistance has no resistors in series. (by F and G)

Proof by restatement of Claim from Premises.
Edit3: Well, not quite: I introduced the Goal at step E.
Last edited by phillipsjk on Thu Apr 29, 2010 4:57 pm UTC, edited 4 times in total.
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phlip
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Re: "Circuit Diagram" Discussion

Postby phlip » Thu Apr 29, 2010 3:01 am UTC

What you're missing is that it's not 1.337 mOhm, but 1.337 mho... aka 1.337 S, or 1/1.337 Ohm.

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phillipsjk
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Re: "Circuit Diagram" Discussion

Postby phillipsjk » Thu Apr 29, 2010 3:30 am UTC

I was not aware of (or did not recall) that dyslexic term for Siemens.

I guess I read it backwards :P
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Re: "Circuit Diagram" Discussion

Postby reevey » Thu Apr 29, 2010 12:17 pm UTC

Anyone else think mouse could be a reference to this comic?
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Ave
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Re: "Circuit Diagram" Discussion

Postby Ave » Thu Apr 29, 2010 4:42 pm UTC

Well we know that this circuit wouldn't work very well considering everything that travels across I-95 grinds to a dead standstill 50%+ of the time.

At least north of New York!

AJHunter
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Re: "Circuit Diagram" Discussion

Postby AJHunter » Wed May 05, 2010 2:09 pm UTC

Y'know what? I was really depressed, then I saw my xkcd facebook thing, clicked on it, and started catching up to where I used to be. I came across this one, and I'm not depressed anymore! ^_^

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Re: "Circuit Diagram" Discussion

Postby wumpus » Thu May 06, 2010 3:25 am UTC

somebody_else wrote:Anyone else notice the PPP transistor (or that's what I think it is). Between the glued open switch and scarab beetles.


That transistor can only be a P=NP transistor.


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