This precision signal rectifier was obtained in an American technical documentation from 1975. The operational amplifiers can be 741 and the power must be supplied from a symmetrical source.
This small analog TV transmitter was found in an Electronics Now from the 90s. The range is around...
This circuit was obtained in a 1970 engineering documentation. The operational is the 741, but...
This mixer configuration from a 1967 publication can be adapted to work with modern transistors. The...