The circuit shown is from National Semiconductor's Linear Applications Handbook. It makes use of the LM78S40 which is not an easy component to obtain today.
This circuit was found in old documentation. It can be made based on modern components. The time...
This small two-transistor AM radio was sold in the 1960s in Japan. The circuit was powered by two...
I found this circuit in an old English magazine from 1979, but it can be easily assembled with...