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.
This circuit is from a Radio Electronics from December 1990. The circuit was used in a home...
This circuit, which combines a bipolar with any JFET, was found in the April 1993 issue of...
This General Electric circuit was found in a 1964 documentation. The circuit triggers a relay when...