Just looking at the first spintronics "circuit" in this video I see a problem. If you take out the "resistor" and just have the "battery" alone, pull the cord

Just looking at the first spintronics "circuit" in this video I see a problem. If you take out the "resistor" and just have the "battery" alone, pull the cord and let go, the "battery" will still spin and lose all it's "charge." In actual electric circuits that won't happen, the battery has to be connected to something to discharge. That breaks the analogy right off the bat. Back in college I was a teacher's assistant for the one electrical engineering class that mechanical engineering students were required to take and I learned just how unhelpful, even detrimental, analogies for electricity are. The professor didn't use any, but the students had heard some water-through-pipe analogies and had questions for me. I quickly figured out that debugging their analogies was not helping them solve the actual circuit problems they needed to solve for the class. It really bugs engineers to not know how something works, but the thing is, nobody really has all the answers to how or why electricity works, and yet we still do amazing things with it. You don't need to know. For example, why is it that moving electrons back and forth in one wire causes electrons to move back and forth in other wires that are miles and miles (light-years even) away (talking about antennas and RF here)? Nobody knows! But we know it happens, we have characterized the behavior quite well, and we have mathematical equations that describe it, and we can do amazing things with the knowledge we do have. Here's what you need to know for basic circuits: V = IR P = IV Power supplies (batteries, wall outlets, etc ) supply power, which you know from the second equation above is voltage and current. Capacitors resist change in voltage Inductors resist change in current Diodes only let current flow in one direction, after a threshold voltage has been exceeded. Amplifiers take in two input powers and add some of one to the other. Transistors (if we are sticking to the digital realm) are voltage controlled switches. In the analog realm transistors are more complicated (but often they can be thought of as amplifiers), but you also don't encounter them in basic circuits unless you start taking apart power supplies and amplifiers. EDIT: almost forgot my favorite thing (somewhat tongue in cheek): all electrical problems are connectivity problems. You either have too much connectivity (extreme being a short circuit), or not enough (extreme being a broken circuit).