Opto control for triac (CB20552E)

Found a documentation for PC from 1992, this circuit is indicated for the English power grid of 240 V.

High Impedance Microphone Preamplifier (CB18257E)
This high-gain circuit uses junction FETs (JFETs) and must be powered by somewhat high voltages. The...
Binary Display 7400 (CB22436E)
This circuit counts 1 per second, displaying the value in binary. The circuit is TTL and must be...
Sensitive Geiger Detector (CB5925E)
Critical components of this project are the Geiger tube and the 300V battery. The battery can be...