31. Electrons were first discovered as the constituents of cathode rays. 32. This forms a solid metal that electrodeposits on the cathode . 33. MPD cathodes are easily corroded due to constant contact with the plasma. 34. A receiver plate ( cathode ) is connected to its negative pole. 35. An electron that leaves the cathode will collide with neutral gas molecules. 36. Cold cathodes sometimes have a rare earth coating to enhance electron emission. 37. Cathode materials are generally constructed out of two general materials : and.38. Zworykin described cathode ray tubes as both transmitter and receiver. 39. Gas flows through the ion source between the anode and the cathode . 40. Tantalum electrolytic capacitors with PPy polymer electrolyte cathode followed three years later.