This series LED circuit was found in the February 1992 issue of Radio Electronics magazine. The effect's speed is dependent on C1 and adjusted by R3.
We find this microphone voice effect in 1992 documentation. The vibration of the relay contacts...
We can also use the 4011 on this CMOS circuit that makes use of a crystal headset. The power...
We found this circuit in documentation from the 1980s. The integrated circuit used is uncommon today,...