| 摘要 |
<p>A directly heated cathode assembly comprises a cathode button 100 having a concave surface, two electrodes 120, 170 positioned on said cathode button such that the application of a voltage between them causes current to flow through the body of the cathode button thereby causing heat to be produced within the body of the cathode button. The current flow is evenly distributed between the electrodes by an arrangement incorporated within the cathode button illustrated as a maze of insulating pieces 220. This maze causes the current to travel in a path substantially greater in length than the distance between the electrodes. <IMAGE></p> |
