This circuit is from a Motorola documentation from 1968. The integrated one is an operational of the time still in metallic casing. Modern equivalents can be used.
This triac circuit was found in the October 1987 Radio Electronics magazine. The triac is...
This circuit was found in a 1987 edition of the United States' Hands-On Electronics magazine. The...
We found this TTL circuit with the 7400 in the January 1975 Radio Electronics magazine. The power...