Electrical engineering a crucial enabling technology for electronic television. John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode. In 1920, Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer. In 1934, the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936. In 1941, Konrad Zuse presented
Vienna valve trombone The Vienna system was in common use in Germany on all kinds of instruments including trumpets up to 1850. Adolph Sax invented instruments with 6 independent valves 3 for each hand, but only the most dexterous musicians were able to play them. The valve trombone has definite advantages over the more common slide trombone, such as taking up less room in a seated orchestra. Verdi, for example, composed passages that would have been impossible on a normal slide trombone. For illustrations of a Vienna valve trombone c.1850, see: Vienna valve trombone Vienna valve trombones use Vienna Valves which were one