The "Guide to " is a handy reference for experienced engineers and a tutorial for engineers who want to expand their knowledge of circuit protection. The 72-page guide covers the different circuit-breaker technologies: thermal, thermal-magnetic, magnetic, and high performance; key terminology; and optional features of circuit breakers. Also included are diagrams and tables. Free copies of the guide are available by calling (800) 462-9979.

E-T-A Circuit Break-ers, 1551 Bishop Court, Mount Prospect, IL 60056, (847) 827-2700,