Triode Triode A triode is an electronic amplifying vacuum tube (or "thermionic valve" in British English) consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode (Fleming valve), the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode. Its invention founded the electronics age, making possible amplified radio technology and long-distance telephony. Triodes were widely used in consumer
John Snell (electrical engineer) Central Electricity Board was established, the national grid created and the supply of electricity standardised. He was made GBE in 1925. In 1928 he began introducing major new electricity power systems in the West of England with his friend and then colleague, Dr John A. Purves. He was awarded the Faraday Medal for 1938 by the Institution of Electrical Engineers (now the Institution of Engineering and Technology). He died after an operation at the London Clinic in 1938. He had married Annie Glendenning Quick of Biscovey, Cornwall, with whom he had at least one son. John Snell (electrical engineer) Sir