Intro to Electricity (26 and 30.1.12)

In our second and third classes, we were introduced to the basics of electrical engineering, focusing specifically on circuits and voltage.  Circuits are comprised of currents with voltage, and have a specific positive or negative charge (charge = Q).  In an electrical field, potential energy is greatest at the source of the field and becomes weaker as one moves outwards in any direction.  To give a particular particle voltage is to place this particle at a specific place and specific level of energy within the electrical field.

Voltage is measured in volts (joules per coulomb) and represents the potential electrical energy in each unit of charge.  To add voltage simply means to place a particle at a particular place within the field of potential energy.  The electric field can me measured with this formula, where E is the electric field intensity, F is the electric force and q is a positive, stationary point charge.

 

http://www.search.com/reference/Electric_field

Work is performed to counteract forces, and electrical fields are conservative, meaning negative work is produced.  Negative work causes a decrease in the intensity of the energy level, so when a particle enters a lower level of energy, the particle's energy is decreased and extra energy is released, usually in the form of heat.  This is because of thermodynamic property of entropy, or the tendency of nature to move from a state of order to one of disorder or randomness.

The First Law of Thermodynamics dictates that a change in internal energy is equal to the heat added or subtracted from a system subtracted by the work performed by the system:

W=△E

Energy is measured by E=∫Fdx and can be normalized by charge Q to equal voltage (electric potential):

An effective way to understand the properties of thermodynamics and electrical engineering is by running a current through a resister, or series of resisters.  A power source, such as a battery, creates a voltage stream of electrons within a system flowing from positive to negative.  This flow of voltage passes through a resister, which absorbs power.  Power in the electrical world is represented by the formula:

wikipedia.com 

Oscar gave us various formulas to measure the voltage running through various elements we might use to build our circuits, such as these:

An important property of resisters is how resisters within the same electrical circuit interact.  Two circuits connect in a chain, one after the other in a straight line, can be added together, so two resisters of 10 KΩ would combine to equal 20 KΩ, wheres two resisters running parallel do not and must be calculated.

Stay tuned for the exciting world of breadboard experimentation...

Welcome to Engineering! (23.1.12)

Здравствуйте! Willkommen!

This will be a digital log of my activities in the Intro to Engineering Class offered at Wellesley College, near Boston.  This class is being taught in conjunction with the Olin College of Engineering as a general introduction to the science (or art, one could argue) of engineering and as a stepping stone to further engineering classes at Olin or MIT.

On our first day of class we discussed what the field of engineering means to each of us, and what we hoped to gain at the end of this semester.  Personally, my interest in furthering my understanding of locomotion and aviation propelled me (no pun intended!) to take this class.  As a child, I was fascinated by trains; my favorite place growing up in Pennsylvania was the Steamtown National Historic Site and Museum in Scranton.  Likewise, as a result of my father working for the legendary Pan American Airways, I was surrounded by model planes and stories of flight.  One of my favorite sensations is the moment the air pressure under the jet wings finally propels it into the sky.  Since my first major plane flight by myself to Germany, I've filmed every take-off and touch-down I've ever experienced.

Another memorable plane experience was while I was living just outside Hamburg, and visiting the town of Othmarschen, about 18 minutes from Hamburg's inner city.  Per usual, I found myself lost wandering through a beautiful residential area when I heard a low grumbling sound and to my amazement, saw an Airbus Beluga soaring overhead.  Lost for words, I did not know what it was, but immediately imagined it a majestic white whale coasting through the clouds.

Now to move on to the actual class; one particularly interesting product of engineering our professor introduced us to is the Lytro photography camera.  My initial impression was, "well okay, a pocket sized, aesthetically pleasing camera that takes square pictures."  That was until I realized how aperture works on this camera.  On a traditional camera, one manipulates aperture and shutter speed to obtain the desired photo (or the camera is programmed with software to evaluate what's being seen through the lens, a.k.a. auto mode).  Aperture controls the angle of the light admitted by the camera and shutter speed dictates how long.  A traditional camera uses one value for each, and produces a single image. Lytro, however, takes a single picture at a range of aperture settings, so a single image, after being taken, can have it's aperture manipulated as though it was hardly a "still" image at all.  As Lytro puts it: "Focus after the fact."

tl;dr  Engineering is fascinating.  Lytro blows my mind.  Oh, and I ♥ planes!