This circuit provides a 5 V negative voltage from a positive input voltage. Found in old American documentation, information on the used integrated circuit was not provided. Probably an oscillator.
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...