When doubts arise ..
No, no one declares that qualified electrician should know, say, the same diodes catalog. No, this is, to put it mildly, too much. In the end, with the development of the Internet, and the cheapness of mobile devices, you can always, if doubts arose, go to the site and clarify the details you need. But in order for these doubts to arise, basic knowledge must be had? It is necessary to imagine that it is dangerous for a microwave, a washing machine, a computer, a server and similar devices.
What is needed for this? Trite, but more read. Good, smart books.
