This circuit was found in an 80's Electronic Engineering. The circuit uses a multivibrator with neon lamps and an optical coupling system.
Found in a magazine 73 for radio amateurs, this circuit has two settings, one for the interval and the...
This good quality amplifier found in a 1982 documentation has a traditional complementary output...
A low frequency divider can be made using common unijunction transistors as shown by the figure...