negative-grid thyratron

negative-grid thyratron

[′neg·əd·iv ¦grid ′thī·rə‚trän]
(electronics)
A thyratron with only one grid, which serves to prevent the flow of current until its potential relative to the cathode is made less negative than a certain critical value.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.