We found this circuit in a spy book from the 90s. Transistors admit equivalents and the coil can be designed as in the CB19425E project. Power is provided by cells or 9 V battery.
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...