It was a lot of fun to re-visit circuit schematics after so many years. I worked on diagrams for three circuits we did in class. The series circuit (where the voltage is re-distributed across the 4 LEDs but the same current passes through all of them), the parallel circuit (where the same voltage is applied across the terminals, but the path of the current is different), and one with a voltage regulator (that converts the high voltage into a lower voltage to prevent damage to the components).