This classic windscreen wiper interval setup was found in American documentation from the 90s. The circuit can be found with variations at other points on this site.
This circuit was obtained from a 1966 documentation. The transistors are of the time. The circuit...
This amplifier circuit with a low power MOSFET was found in Popular Electronics from the 90s. The...
This circuit was found in American documentation from the 1960s. The operational amplifier is from that...