41. The vacuum tubes indicated in Hewlett's patent were pentodes rather than the triodes shown here. 42. However, tetrodes are successfully used into the VHF range and triodes into the low GHz range. 43. The grids of the triodes are arranged so that only one digit is illuminated at a time. 44. After the war, Shockley decided to attempt the building of a triode -like semiconductor device. 45. A "'triode "'is an electronic radio transmitters and industrial RF heating devices. 46. A triode has three electrodes : the anode, cathode, and one grid, and so on. 47. Thus a pentagrid radio could easily be converted to a triode -hexode without any other circuit modifications. 48. He was the first to give a correct explanation of how De Forest's triode tube worked. 49. This circuit design has been used at 1296 MHz using disk seal triode valves such as the 2C39A. 50. He started working on triodes and invented ( with his director Gilles Holst ) the penthode in 1926.
