Why decoupling capacitors exist, and why placement beats value

Why this mode exists

Decks, exams and labs all test what you already met somewhere else. That works when you arrive with prior exposure — it does not work for a domain that is new to you, where nothing on this site ever taught the concept in the first place. A lesson is where the concept gets in. It is deliberately harder to click through than a page of prose: the guessing, the questions between sections and the write-before-you-look step are the parts that do the work. How to Learn explains the evidence behind each one.