Harold, If your students are doing anything with RF, I recommend: Practical Radio Frequency Test and Measurement : A Technician's Handbook (Paperback) By Joseph Carr ISBN: 0750671610 One of Joe's many excellent books. Dave Challis -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist