We found this circuit in the October 1980 issue of Radio Electronics magazine. The circuit uses general-purpose transistors driving a relay.
This small preamp for low impedance microphones was found in a Popular Electronics from November 1968....
The CA3162E and CA3161E pair were widely used to create a 3-digit digital display. This basic...
This circuit, which uses common components even today, was found in a 2001 documentation. It is an...