The integrated circuit used in this trigger is uncommon today. We found it in a documentation from the 70s. The circuit operates with signals up to 50 kHz.
This circuit was obtained in a 1973s documentation. The transistors may be BC558 for the PNP and...
Some old record players use variable reluctance phono pickups, requiring a special amplifier...
This circuit was found in a General Electric documentation from 1966, It applies to any triac and...