We found this circuit in the April 1993 Electronics Now magazine. Almost any general-purpose JFET can be used. Power is supplied by a battery (2 x 9V).
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,...