[Amps] Thoriated tungsten lifetime when idling tspa

[Peter Chadwick]

There can definitely be a problem running oxide coated cathodes for a long time without drawing current: it leads to a build up of cathode interface resistance, and according to one of my textbooks (I hesitate to admit owning one on pulse and digital circuits, being somewhat akin to admitting to owning pornography !) it was a major cause of failure in early tube computers.
73
Peter G3RZP