This 80-minute class focuses on direct current circuits. As the video begins, Jacobsen is taking questions from the students before class as they come in. He repeats them for the whole group. One question leads him to ask, “How many of you work with someone else on the homework?” It’s definitely a good idea, he says, because the purpose of the homework is not just to survive it, but to learn “the stuff.” But he points out that there are good and bad ways to study together. “What answer did you get?” is not the best kind of question to ask; rather, “How did you solve that?” He begins the lecture by summarizing very clearly and in discrete steps what they will cover: simple dc circuits (“We’re going to abstract away all the details”), which will involve talk about a problem-solving approach; then explaining “equivalent circuits,” a “very powerful” technique for thinking about circuits. Finally he will provide a specific case of how an electrical circuit works. Jacobsen doesn’t do all the boardwork in advance, as in some other large classes, but creates it as he goes. Of note throughout the lecture is the directness, simplicity, and clarity with which he presents the ideas. He reinforces that with reminders (“Let me remind you that we know four things about circuits”), rhetorical questions (“What do we do now?”) and answers “We have two choices”). The emphasis is always on the simplicity; “So we’re approaching this problem in a way that is intuition-free, just solving little pieces as we go”; “Resisters in a series behave in a simple way. You just add them up.” At one point he gets stuck, admits it, and turns this to his advantage by throwing up his hands and saying, “Too much algebra,” which is the very point he has been making all along, and he later says, “It was probably matter of pride that I thought I could do this on the board by doing the algebra. But the physics is very simple.” He provides an excellent demonstration of the circuits with a circuit board that has been designed to look exactly like the one he has drawn on the board.