Opto control for triac (CB20552E)

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

Video Modulator (CB14572E)
The circuit shown is from Motorola's 1990 Linear Databook. Shaded components are optional. The...
Accented Metronome (CB5336E)
This circuit was found in an ancient American documentation. The transformer is the type used in...
Long period integrator (CB6843E)
Suggested by National Semiconductor in documentation from the 90s, this circuit makes use of an...