This benchtop power supply with various output voltages from 1.5 to 12 V was found in Radio Electronics magazine from August 1960. The circuit uses power transistors of the time.
This sensitive photo-diode circuit with output compatible with TTL logic was found in a 1972 RCA...
This circuit can send signals in both the VHF and FMN bands with a range of a few tens of meters. The...
This circuit was found in a Popular Electronics from the 80s. It is possible to control a relay...