My sophomore lab instructor told us that we should save our lab books because we'd be looking up the formulas we derived the rest of our lives.
I tossed mine. But my roommate kept his and he did admit years later that he consulted his sophomore lab notes regularly.
E = IR relates current and voltage.
Series R is a voltage divider.
Parallel R is a current divider.
Lumped R simplifies circuit analysis.
Power Transfer into loads.
Capacitors and Inductors
Reactance is Like Resistance at one frequency.
Capacitors Integrate Current and differentiate voltage.
Inductors Integrate Voltage and differentiate current.
Breakdown Voltage limit storage.
Core Saturation limits storage.
Resonant Circuits and their quality (Q).
See also One Hundred Steps to understand computing.
See 17 Awesome Equations that changed the world.
See Trigonometric Functions transformed.