This watch uses a liquid crystal display. The circuit is from the 80s and the module used is uncommon nowadays. Power is provided by a single cell.
The normal use of a 4520 as a divide-by-16 counter is shown in Figure bellow. In the normal...
This flasher was found in an 80's Electronic Engineering but can be easily implemented with modern...
This micro-transmitter for the FM band was found in documentation from the 90s. The circuit is...