These circuits were obtained in an Electronics Now from the 90s. The integrated circuits are from that time and the power can be between 1.5 and 2 V.
The circuit shown is from Motorola's 1990 Linear Databook. Shaded components are optional. The...
This circuit is from an English magazine of 1977. The circuit is still current, just using BC547...
This circuit is from a 1986 Revista Española de Electrónica. It consists of an amplifier with...