Trade schools cover more of this stuff, but most without prior knowledge are not given enough to fill the gaps, and have it click, meaning they know some keywords, but no idea how to apply it,
I was in a high level class discussing how to measure current and voltage in an industrial setting, and that it was difficult and expensive to interface to computer control systems... yeah I had a double take. Equally things like Wheatstone bridges drawn with inductors, and other non valid symbols.
I actually completed 2/3 rds of my 4 year course in 1 week, by demonstrating my understanding of the concepts by ripping in to a pile of stuff they had sitting around for repair for the past 5 years, (it meant I only had to pay 1 semester, so I wasn't too fussed on payment) Oh you want me to show ohms law at work... well this fuse has 25V across it, so its resistance must be high..
Though the fun came from what form of programming they had on hand, they had very old gamepad programmed PLC's that used ladder logic, where I would solve the problem then reduce it down to the smallest possible solution. made anyone in the class copying my work stand out like a sore thumb. and resulting in test scores along the lines of "100%, It works, but hell if I know how?"
Back to the original topic, online schematics had me throw away a lot of money early on, It takes a while to build up enough Google-Fu to know when someone is talking about something they understand. and there is a stupid amount of simple circuit images out there that plain and simply will never work without the understanding of the weird quirk they used.