We found this circuit in the February 1983 issue of Radio Electronics magazine. The 4-digit circuit is based on dedicated integrated circuits of the time. The power supply is not shown.
August 2017 - Mouser Electronics is announcing the availability of TDK ICS-52000 microphones with...
This circuit was obtained from a 1986 Spanish magazine Resistor. The magazine no longer exists, but...
This comparator application circuit was obtained from the June 1986 Radio Electronics magazine. The...