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 in an English documentation from the 60s. The integrated circuits are the...
This circuit has a 60 dB gain and a bandwidth of 68 MHz. We find it in Maxim's documentation. ...
The aim of this circuit is the protection of a 2N3055 transistor, avoiding the overheat. The...