This circuit of an Electronics Hobbyists Handbook uses a different configuration for a triac. The circuit uses an integrated frequency divider and a coupler with a fotodiac.
In the original circuit a 40431 quadrac is used, but this is not a common component today....
The critical components of this 1978 circuit are transformers, which, hopefully, can be obtained from...
We found this circuit in the October 1993 Electronics Now magazine. The 4-channel circuit is...