Grandpa and Little Johnny are sitting on a bench in the park. Johnny asked, "Grandpa are you going to take that new Viagra?"
Grandpa looks at him and says, "No Johnny, I will not."
"But Grandpa, why?" asks little Johnny.
Grandpa replies, "Because there is no sense in putting lead in your pencil if you have no one to write to."
Three element vacuum tubeIn 1907, the three-element vacuum tube was issued a U.S. patent to its inventor, Dr Lee de Forest as a “device for amplifying feeble electric currents - such, for example, as telephone currents” (No. 841,387). The tube was evacuated, with some remaining conducting gas molecules, and it was suggested using for the heated electrode such material as platinum, tantalum or carbon. He had made a public annoucement of his device a few months earlier, on 20 Oct 1906 at a meeting of the American Institute of Electrical Engineers held in New York City. On 18 Feb 1908, he received another patent for the grid electrode tube (No. 879,532). |
