This experimental bench source was found in a modern book on tubes. The components used can be easily obtained.
This circuit was found in a 1968 Motorola documentation. The circuit can be implemented with...
This 1000: 1 voltage-controlled filter circuit was found in an Electronics Today International in a 1980s...
The Toshiba TLP577x series consists of an infrared photo-emitter (IR) and a sensor integrated circuit...