This flasher was found in an 80's Electronic Engineering but can be easily implemented with modern general purpose transistors. The frequency depends on C1.
We found this filter in the 1990 Motorola Linear Databook, but it can be implemented with other...
This circuit is from Linear Technology 2005 documentation. The circuit is based on company...
This circuit sources a ramp signal with characteristic given by the diac. The circuit is powered...