“Some people collect stamps, coins or baseball cards, I collect electronic circuit schematics. I own several book shelves and file cabinets full of electronic circuit books, IC application manuals and circuit encyclopedias. I often use my collection for reference.”
David A. Johnson, – P.E. consulting electronics engineer.
(This resource by dave is very important for Electronic Enthusiasts, Engineers and R&D Engineers. I say this as an R&D Professional with more than 20 years off the ground)
Capacitance Proimity Switch Technology -The Design Corner, Imagineering E-Zine. These are the type of technologies that lead to the Touch Screens on Tablets and Phones.
“These switch circuits used a sensitive high impedance circuit to detect the small AC power line signals, picked up by the human body from nearby appliances.”