Eletronic Clock The Thermoionic or electronics valves, as it is known, is due to Du Fay’s researches in 1733, Becquerell in 1853 and, mainly to the Edison’s works, that took him to discovery in 1884, the thermoionic emission that received the name of "Edison`s effect". That valve with two electrodes can only be used when Lee de Forest, 1907, introduced a new element, and applied it with success in the wireless telegraphy transmissions. In 1930, Morrison built at Bell Telephone Laboratories, in New York, the first clock made with crystal of quartz. Those clocks, as well as the others built until the transistor coming, were enormous and complex, exclusively destinated to laboratories of researches or astronomical observatories. |
