This interface shield circuit is from the 1983 Intersil Databook. The components used are uncommon today. ADCs are low-cost digital converters. The power source voltage must be 5 V.
This simple two-transistor receiver was found in Radio Electronics magazine from September 1960....
This circuit was obtained from the February 1992 Radio Electronics magazine. In it, a bar of 4...
This old integrated amplifier is from a Japanese publication from 1972. The integrated circuit is...