We found this circuit in the Encyclopedia of Electronic Circuits Volume 5 from 1995. It uses a 3-terminal transducer from the time. The circuit is triggered by light.
August 2017 - STMicroelectronics' new T850 switches with triacs up to 8 A can be obtained from...
This circuit is from the 1990 Motorola Linear Databook. The circuit can be applied to other...
Found in documentation from the 90s, this circuit makes use of components from the time....