This 5 V power supply was found in the January 1992 issue of Radio Electronics magazine. The integrated circuit must be equipped with a heat sink and the current is 1 A.
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,...