This circuit was found in the February 1983 issue of Radio Electronics magazine. It is a 4-digit circuit with dedicated integrated circuits, with no power supply indicated.
This circuit for the medium wave range was suggested by a Popular Electronics from the 90s. The...
This version of a call-fish is from 1981 using, for this reason, a 90 V battery that is no longer...
This musical doorbell was found in a Popular Electronics from the 90s. The U4 melody generator...