The inventor of the vacuum triode is American scientist Lee de Forest (1873-1961). In 1904, Fleming invented the first electron tube by adding a plate in front of an electric wire (filament) heated in a vacuum. He called this kind of electron tube with two poles a diode. Using the newly invented electron tube, the current can be rectified to make the telephone receiver or other recording device work. Nowadays, when we turn on an ordinary tube radio, we can easily see the tube with its filament burning red. It is the heart of electronic equipment and the starting point for the development of the electronic industry