Found in a 1967 American electronics magazine, this circuit has an input impedance of 2000 ohms. The circuit can be built with modern equivalent transistors.
One flip-flop of the 4018 can be used as a frequency divider or counter as shown here. Frequency...
A low frequency divider can be made using common unijunction transistors as shown by the figure...
We found this circuit in a 1987 magazine, but the use of still common components allows its...