You Need More Than Cookbooks [White Hot

Abstract

You don’t learn how to cook from a cookbook.” This came to me while planning the teaching of this past semester’s power electronics project lab. In a previous column, I talked about teaching a project lab at the University of Colorado–Boulder for master’s students who were going into industry and not continuing for a Ph.D. degree. The goal of the project lab is for the students to do an original design project under conditions as similar to industry as possible. Rather than a weekly “build this, take data, write a report” of the typical university lab class, these students are given a specification and a schedule. The students are told “what,” they are not told “how.” They are also given a standard parts library, component derating guidelines, and product safety requirements. Some of the instructional objectives are learning to design with ac mains power, learning to design for a wide range of operation of both input voltage and output load, and learning how to debug an original design. The major goal of the class is to demonstrate working hardware at the end of the semester. The project is a 25-W constantcurrent output LED driver that must work from a universal ac input (85– 264 Vac) and vary the LED current from 0 to 1,200 mA, as the dimming control voltage varies from 0 to 10 Vdc.