CS Course Day 36

Yesterday I finally started 6.002x Circuits and Electronics. I have until May to complete the 3 modules. My motivation is: it's not enough to learn programming skills; if I want to build integrated hardware systems... well I better know which wire goes where eh? I like the course. Worked on it yesterday from 1800 to 23:40 with some breaks. It feels good to work on things from a coding side, and from a physical and math pencil & paper side.

I worked on some very basic circuit analysis. The course at this stage is a review. KCL, KVL, element relationships, and node-method analysis. I first tried this course maybe 10 months ago and where everything seemed like impossible black-magic it's now pretty simple and intuitive. You stay consistent in how you assign [$+$/$-$] and math + principles basically takes care of it all for you.

For example, down below at S2E2 your asked to find the branch variables of the two circuits. The only difference between the two is that the sign convention (which way is [$+$] or [$-$]) on the voltages is switched. As you'd expect, the measured voltages and currents are the opposite signs of one another, but the power being supplied by the voltage source and dissipated by the resistor is the same.

These in-lecture exercises served as a warm-up for me: remembering the mental habits that make you efficient; but in the beginning you grind through it all so it takes some time. S2E3 at bottom was a more involved application of everything.

S2E2 & S2E3:

I got as far last night as dealing with the Node method. The other methods (KCL/KVL and element relationships) balloon in complexity and number of equations with number of elements. The node method is what's used. The way it works is you pick a node (a juncture between branch elements) and set that as your ground. You're measuring voltage which is a potential difference, so it doesn't matter so long as you're consistent. After that you write your KCL (Kirchoff's Current Law) equations for each node summed to zero. The convention I'm using is: current out = [$+$], current in = [$-$]. You then solve for the node and once you know your node voltages, calculating the remaining branch elements is easy: just a case of $V = IR$

I have SICP work to get to now so I'll cut this short and pick up another time. I'll have to make pictures of the notes clearer.