Philip Mayo thinks this is interesting: These vacant positions are called holes. From 1. Basic Concepts, Laws, and Principles from Basic Electrical and Electronics Engineering by D. Devaraj, S. K. Bhattacharya Publisher: Pearson India Released: August 2016 Note This is a spurious comment and not entirely accurate. Share this highlight http://learning.oreilly.com/a/basic-electrical-and/20537167/ Twitter Facebook Google Plus Email Get Instant Access Now Start a Free Trial Have an account? Sign in.