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
Triode in mass-marketed consumer electronics, having been overtaken by less expensive transistor-based solid-state devices. However, more recently, vacuum tubes have been making somewhat of a comeback. Triodes continue to be used in certain high-power RF amplifiers and transmitters. While proponents of vacuum tubes claim their superiority in areas such as high-end and professional audio applications, empirical evidence shows that the solid-state MOSFET is virtually identical in performance. In triode datasheets, characteristics linking the anode current (I) to anode voltage (V) and grid voltage (V) are usually given. From here, a circuit designer can choose the operating point of the particular triode.