Category Archives: Uncategorized

Free Energy

So I’m fairly upset with myself for not working on my latest Circuits assignment a lot earlier…

I turned it in at the end of class today, but I’m not hoping for much. Why not, you ask? Well, let’s just say I had to start fudging calculations when I found an input resistance of -5002.14 ohms. (I arbitrarily dropped the negative…)

Non-nerdy explanation of why that’s bad: Short answer: It’s impossible.

Long answer: You can imagine the circuit I was looking at like a water pipe with a filter/funnel in it. The filter is designed so that for just a small amount of water going through, it’s not too hard and the water pretty much goes right through. But, the more water you try to send down the pipe, the more “clogged” the filter gets, and the harder each molecule of water has to work to get past the filter. How “hard” a molecule has to “work” is like the resistance number I calculated for my circuit: Maybe the filter is designed so that each molecule needs 500 Joules of energy to get past the filter, per gallon of water that flows through. So, if 1 gallon flows, each molecule needs 500 Joules. If 2 gallons flow, each needs 1000 Joules, and so on. The more water flowing, the more energy needed. This is basically how resistors in electronic circuits work.

Now imagine what it would mean if that number was negative… i.e., you get energy back by pushing your way through a filter. And you get more back the more water there is. It doesn’t make any sense, which is why I know my homework is wrong. 🙁

To quote Wikipedia, “Absolute negative resistances without an external energy source cannot exist as they would violate the law of conservation of energy.”

:sad face:

Road Trip!

I’m off to Michigan Tech. University in Houghton, MI to visit Scott this weekend. Ashley, Jared, and I will be driving up this afternoon and back down Sunday. Should be a pretty awesome time: I haven’t been up there in two years.

Have a good weekend, everyone else!

Light-dependent LED reverse-bias voltage discharge times (my 453 design project)


Light-dependent LED reverse-bias voltage discharge times (my 453 design project)
Originally uploaded by CCmcGeek.

Measuring the light-sensitive fall time of the voltage across a reverse-biased LED. The LED essentially acts like a variable capacitor, so the RC constant of the exponential decay depends on the intensity of light hitting it. We observed significant variations in fall time with one LED being exposed to ambient light vs being covered with a hand. Unfortunately, we aren’t getting any kind of useful results when we include more than one LED in the circuit… stay tuned for more details.

Maybe I Should Graduate?

Update: I misread one of the requirements for the Computer Engineering degree. I actually need two advanced elective ECE courses, instead of 1 CS. [/Update]

I’m not sure if I’m going to be able to hang around here for a full 4 years or not…

I ran my DARS (Degree Audit Reporting System) report today to see what’s left for next year. Answer: 3 courses.

I can graduate if I take (Updated):

  • Engineering Professional Development 397: Technical Communication
  • Computer Science 577: Introduction to Algorithms OR Computer Science 520: Intro – Theoretical Computer Science
  • Any one additional Computer Science course numbered over 400.
  • Any two additional Electrical and Computer Engineering courses numbered over 400.

That’s it. I could sleep from now until December 2007 and still graduate. Maybe I should have taken 17 credit semesters and graduated this year?

Now I have to decide what to do: I can easily graduate in December, or I could take a lot of courses that I’m interested in and stick around until May 2008. Any advice?

Things I Learned Today

  1. Metal is very cold when the air is 14 degrees, and an excellent conductor of heat. It will, in fact, suck all the heat out of your hands. This is not safe when you are outside atop a 15′ aluminum tower.
  2. Heat conduction goes both ways. You should never turn on a heater on one side of a piece of metal, and then touch the other side to see if it’s hot. It is. Even if the air outside is only 14 degrees. You’ll still burn some fingerprint right off your finger.
  3. When snow reaches the top of a water spillway which you know to be about a foot deep, stepping in it will result in snow going over the top of your otherwise waterproof boots.
  4. Just because you push water into one end of a hose does not imply that it will come out the other. In fact, it does not imply that it will come out at all. I have, in fact, no idea what happens to it.
  5. The mister nozzle does not work 🙁

College male seeks more heat in relationship

Dear downstairs neighbors of University Heights Apt 60,

I just wanted to drop you a note to thank you for running your heat earlier this year during the cold snap before Winter Break. Dave and I very much appreciated your generous donation of your unused BTUs.

That said, I think our relationship has been moving in a new direction lately, and I’m not comfortable with it. In fact, it’s been getting downright chilly. Frigid, even. I greatly fear for our continued friendship if you are not prepared to turn up the heat in our relationship a little bit. And I think you know what I mean by “turn up the heat.”

Now. I’m freezing.

Always Yours,
Colin

P.S. – Sorry about the noise. Nate bought a new subwoofer, and it’s fun 😀