Sunday, April 29, 2012

[6.002x] Fourth lab session

Hello all,

The midterm is now over! 

The next lab assignment (attached) will introduce you to capacitors and inductors.


[Link: Lab worksheet]

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My LC ringing test:

Below, a toy DC motor is used as a generator to produce voltage:
  • A battery-powered motor drives a second motor which is used as a generator. The two motor circuits are electrically isolated.
  • The output of the "generator" (yellow scope trace) is cleaned up with a diode and capacitor (blue trace).
  • The cleaned DC output is used to power an AVR microcontroller, which is running a "LED blink" program.
Kind of nifty setup. Inspired by several students here who are interested in power generation.

Wednesday, April 25, 2012

Interesting sensors and electronics parts

Hello all,

An interesting website that sells electronic sensors and parts is
where I bought many of the parts that I brought to Mongolia.

You might find it interesting to browse the "Sensors" and "Robotics" sections (or all other sections!). If you find a particular item interesting, and you want to try building projects with them, please let me know!


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Possibly the first "Blinky" in Mongolia?

Monday, April 23, 2012

The Gobi Desert

Last weekend, we went down to the Gobi Desert to visit the "Oyu Tolgoi" copper mine.

We landed here, a ger airport:

In the middle of the desert, the Oyu Tolgoi copper mine has been built in the last 27 months:

Conceptually, the mining operation is simple. Rocks with copper content is dug from the ground, which are then crushed in large washing-machine-like apparatuses. (The large rocks are put into the "washing machine" with steel balls. As the machine turns, the steel balls crush the rocks.) A chemical process is then used to extract "copper concentrate" from the crushed rocks, for further (off-site) processing.

Going into the facility:

Inside. The previously-mentioned washing machines:

This is where the workers live:

This is a ger where we spent a few days. Originally, the trip was supposed to last one day, but because of sandstorms in the desert the planes were cancelled and we stayed an extra two days.

What else is in the desert? Horses, camels, goats, sheep and their nomad owners. The desert is vast:

In addition, there are also petroglyphs of unknown age:

Wednesday, April 18, 2012

[6.002x] Exam preparation

Hello all,

In preparation for the upcoming midterm, please try the two "example exam questions" (go to "Course Info" and see April 9th announcement). It will show you the format of the midterm,


Monday, April 16, 2012

Building circuits outside

Power outage at the school today. Some students opted to build circuits outside using the big solar panel:

Sunday, April 15, 2012

[6.002x] Third lab session

Hello all,

The third lab assignment is attached. The focus of the exercise is small-signal analysis.


[Link: Lab worksheet]

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My speaker amplifier (common-source amp followed by source-follower):

[6.002x] Schedule for this week

Hello all,

This week, I will cover:
  • Small-signal analysis (Wednesday)
  • Capacitors (Friday)
Enky will be present during the lectures for translation into Mongolian since we are tackling challenging concepts.

In addition, please watch the 6.002x Week 6 lectures -- "Small-signal circuit models" and "Capacitors and first order circuits" -- in preparation for the Sant school class. Also read Chapter 8 of the textbook for further background.

See you tomorrow,

Saturday, April 14, 2012

Students working together

Students teaching each other in Mongolian. It is extremely helpful for conceptually tricky topics such as small-signal analysis. One student figures it out and passes it on to the rest (that's the idea anyway!):

Friday, April 13, 2012

[6.002x] Small signal discussion

Dear all,

For more information on the small-signal model, please see Chapter 8 of the textbook (Agarwal & Lang). You can access the book on the 6.002x website. I also have a physical copy of the book at the Sant school if reading a real book is more convenient. As always, you're also welcome to come and chat with me in Room 104.


Thursday, April 12, 2012

Monday, April 9, 2012

Lab logistics -- breadboards

Currently, I am meeting students (in groups of 3-4) for an hour three times a week for electronics lab. The students come to lab and work on the breadboards that we keep in lab. In the future, it would be nicer to have one breadboard per student that they can take home. This would allow students to inspect the circuits at home, as well as give better continuity between sessions.

Sunday, April 8, 2012

[6.002x] Second lab session

Dear all,

Here is the assignment sheet that you will be working on in the coming week. Sorry for the belated delivery!

Please turn in lab assignment #1 on Wednesday in class.

See you tomorrow,

[Link: Lab worksheet]

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