This conventional 4 channel circuit with the 4017 and 555 was found in the November 1991 Radio Electronics magazine. The potentiometer can be 47k and it controls the speed of the effect.
We found this circuit that converts a direct voltage into a proportional frequency signal. The...
An application for the previous circuit (CB109) is shown here. The central frequency is determined by C and...
This circuit was found in an Electronics World of 1969. The components of the time. The...