We found this circuit in a 70s Electronic Design documentation. The circuit uses general-purpose transistors from the time. Linearity is better than 0.25%.
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...