At the heart of modern power electronics converters are power semiconductor switching devices. The emergence of wide bandgap (WBG) semiconductor devices, including silicon carbide and gallium nitride, promises power electronics converters with higher efficiency, smaller size, lighter weight, and lower cost than converters using the established silicon-based devices. However, WBG devices pose new challenges for converter design and require more careful characterization, in particular due to their fast switching speed and more stringent need for protection.

Since 1892, Harvard University, like many distinguished academic institutions, has compiled a hymnal for use in its own worship services. The fourth edition of The Harvard University Hymn Book represents the culmination of a ten-year process of revision and re-creation based on the 1964 third edition. Containing over 370 hymns, over 100 more than its predecessor, the book includes many that have become a regular part of worship at The Memorial Church in the years since the publication of the previous edition.

In addition to many familiar hymns old and new, the fourth edition includes selections that were unique to the previous editions, hymns previously unpublished, and other noteworthy “discoveries” that have not appeared in print for many years.