This circuit was found in an American 1990s documentation. It can directly trigger a triac when light is detected by the sensor. The integrated circuit is common, like the 741.
The circuit illustrated in Figure allows external loads (8) to be driven from parallel port...
This circuit uses two transistors to simulate the action of an SCR on a regenerative switch....
The filter presented is from 1994 but can be implemented with a more modern equivalent. We found...