Why do people keep asking these questions on our site? What could we do (in particular, what could we add to the FAQ intro text) to avoid these in the future?
Rather obviously, because there's a group of you who've chosen to define what an allowable question is far more narrowly than a reasonable person would.
Most people would assume that a question which requires the application of skills in electrical circuit analysis for example would fit better here than on any of the other stack exchange sites.
You've chosen to enact with your votes a defacto policy otherwise - but while you can close or migrate question after question, you can't change how new people think and thus where they initially try to post. That's why you get a "practically limitless population" of people unaware that they are about to become "offenders"
Perhaps it's time to consider that the site might grow its community by being a little bit more open to the diversity of questions which have substantial electrical engineering content.
30 questions out of 5700 doesn't seem too bad. It takes work and education. Many of us in the community are helping to close or flag off-topic questions.
That's the price to pay for the StackExchange philosophy, where each question is appropriate for at most one StackExchange site. (the upside being that this site stays focused on-topic.)
Following a few lucrative fund drives, some borderline legal IP trace-backs, and a few cans o' Whoop Ass, it's entirely possible to find those that posted the questions and offer some painful advice, via knuckle, elbow, and heel.
Once this plan matures, I will step back and accept only a 78% cut of the initial funds.
Seems like this orphaned question needed some kick./kick