The presented circuit uses an opto-SCR. We found the circuit in the GE semiconductor manual. Equivalent triacs, depending on the load current and voltage, can be used.
The circuit shown in the figure below is suggested by ON Semiconductor (www.onsemi.com), based on...
This control is intended for 110 VAC or 220 VAC Motors. Any TIC series triac can be used according the power...
This circuit was found in a 1999 English magazine, but can be easily assembled with BC548...