This circuit is from an article that teaches how to assemble it in the magazine Electronics Now from July 1993. It uses a liquid crystal display module from the time with 3 and a half digits.
This circuit from the 90s has RIAA equalization with a gain of 35 dB at 1 kHz. The circuit has an...
This two-way switch or control shows how to control a lamp from two points. This version is from a...
This complete single cell protection system is suggested by Linear Technology in its 2005 manual....