This circuit produces sounds of 6 different notes depending on the keys activated. The circuit is from a Radio Electronics from May 1965. The transistor must be equipped with a heat radiator.
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...