What's the "een" in Halloween?
An electron tube used mostly for signal amplification, consisting of a cathode and anode (or plate) as in a diode, and an intervening wire mesh called the control grid. With little voltage on the grid, large currents can flow between the cathode and plate, but small variations in the voltage on the grid cause large variations in this current, allowing for large amplification of a signal applied to the control grid. See also pentode, tetrode.
electronelectron tube consisting of three electrodes-cathode filament, anode plate, and control grid-mounted in an evacuated metal or glass container. It has been used as an amplifier for both audio and radio signals, as an oscillator, and in electronic circuits. Currently, small glass triodes are used primarily in low-distortion audio amplifiers, while larger triodes, made of metal-ceramics for ruggedness, are used in radio transmitters and in the generation of radio frequency for industrial heating applications