Hi Al,
I believe that creating a product that serves its purpose without making it more complicated than it needs to be is key for an electronic designer, today and in the future.

Going by the project description in the first post (ie temperature control (with PID) of a fish tank) I do beleive that low frequency PWM will work just as fine as a phase angle control but will be easier to implement, produce less electrical interference, require less parts and be easier to build - and it'll work on 50 and 60Hz mains without paying special attention. That's good product design in my book but I don't work as an electronics designer, I don't have a degree and I never went to university so what the heck do I know.

If the students gets assessed by what they CAN (possibly) create then by all means, throw everything you got at it. Phase angle control, datalogging, GLCD with trend charts, TCP/IP interface, you name it. But I hope they gets assessed by their abillity to indentify the real needs to solve the problem at hand and then design a product that works - properly of course.

I DO agree that the correct method should be used. If phase angle control in this application offers benefits that justifies the extra complexity then it IS the correct choice.

Well, that's my view on it. 10-4

Sincerely,
/Henrik.