Opto control for triac (CB20552E)

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

S-meter (CB1405E )
The S-meter is signal strength meter, coupled to telecommunications receivers to indicate the...
Standard Crystal Oscillator (CB5127E)
This is a common crystal oscillator configuration with 80s transistors. The circuit has the...
Battery charger (CB1225E)
This 6 V battery charger was found on a 1987 Hands On Electronics. Rc determines the charging...