Opto control for triac (CB20552E)

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

Dip meter with tunnel diode (CB23732E)
This circuit was found in Radio Electronics magazine from April 1961. The device has a slot for...
FET Follower (CB6132E)
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...
Electronic fuse (CB8352E)
Found in a 1968 Motorola manual, this DC circuit uses components from the era. The circuit fires in...