Found in ancient American documentation this circuit uses semiconductors from the thyristor family such as SCRs, Triacs and unijunctions. The circuit can control loads up to 550 W with the indicated triacs.
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...