low-impedance switching tube

low-impedance switching tube

[′lō im‚pēd·əns ′swich·iŋ ‚tüb]
(electronics)
A gas tube which has a static impedance on the order of 10,000 ohms, but zero or negative dynamic impedance, and therefore can be used as a relay and transmits information with negligible loss as well.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.