The integrated circuit used in this old configuration is not common today. In it we have the way to control two SCRs in a control circuit connected to the AC network.
Mouser has a huge list of sensors for the most diverse applications such as automation, IoT,...
This low-noise, low-drift amplifier was found in a 90's EDN. It can be implemented with modern...
This converter for the 150 MHz band was found in an American documentation. Transistors are...