The circuit is from the MC1539 manual, an operational one close to the 741. The transistor admits equivalent and must be mounted in a good heat sink.
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...