Found in an Electronic Design from the 80s, this circuit uses an unusual component today, the regulator integrated circuit. MOSFET can be almost any type.
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...