Nuvistor

a microminiature metal-ceramic radio receiver tube (triode, tetrode, or pentode) in which the cylindrical working surfaces of the cathode, grid, and plate are arranged concentrically; the nonworking surfaces are conical. The nonworking parts are used to fasten each electrode rigidly to a ceramic disk in the base of the tube by three pins, one of which is the electrode terminal. Nuvistors are used mostly in small, highly reliable radio apparatus, mainly in the input stages of low-noise amplifiers and as heterodynes. Nuvistors are manufactured for operation at frequencies of 400–800 megahertz under high vibrational loading (with accelerations up to 15 g) and in a wide range of temperatures (from –60° to 250°C). Their noise resistance is of the order of 100 ohms at plate voltages of 27–120 volts.