Despite being found in a 1980 publication, this circuit uses components that can still be found easily. The circuit feeds an array of LEDs that run randomly, stopping at one.
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...