The nuvistor is a type of

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as ...

announced by

RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...

in 1959. Nuvistors were made to compete with the then-new

bipolar junction transistor A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipola ...

s, and were much smaller than conventional tubes of the day, almost approaching the compactness of early discrete transistor casings. Due to their small size, there was no space to include a vacuum fitting to evacuate the tube; instead, nuvistors were assembled and processed in a vacuum chamber with simple robotic devices. The tube is made entirely of metal with a ceramic base.

Triode A triode is an electronic amplifying vacuum tube (or ''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 ...

s and a few

tetrode A tetrode is a vacuum tube (called ''valve'' in British English) having four active electrodes. The four electrodes in order from the centre are: a thermionic cathode, first and second grids and a plate (called ''anode'' in British English). ...

s were made; Nuvistor tetrodes were taller than their triode counterparts. Nuvistors are among the highest performing small signal receiving tubes. They feature excellent VHF and UHF performance plus low noise figures, and were widely used throughout the 1960s in

television set A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...

s (beginning with RCA's "New Vista" line of color sets in 1961 with the CTC-11 chassis), radio and high-fidelity equipment primarily in RF sections, and oscilloscopes. RCA discontinued their use in television tuners for its product line in late 1971. Other nuvistor applications included the

Ampex Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name AMPEX is a portmanteau, created by its founder, which stands for Alexander M. Poniatoff Excellence.AbramsoThe History ...

MR-70, a studio tape recorder whose entire electronics section was based on nuvistors, as well as studio-grade microphones from that era, such as the AKG/Norelco C12a, which employed the 7586. It was also later found that, with minor circuit modification, the nuvistor made a sufficient replacement for the obsolete Telefunken VF14 tube, used in the Neumann

U 47 The Neumann is a large-diaphragm condenser microphone. It is one of the most famous studio microphones and was Neumann's first microphone after the Second World War. The original series, manufactured by Georg Neumann GmbH between 1949 and 196 ...

studio

microphone A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and publ ...

. Tektronix also used nuvistors in several of its high end oscilloscopes of the 1960s,http://w140.com/tekwiki/wiki/Nuvistor TekWiki Nuvistor article before replacing them later with

JFET The junction-gate field-effect transistor (JFET) is one of the simplest types of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically controlled switches or resistors, or to build amplifi ...

transistors. Nuvistors were used in the

Ranger program The Ranger program was a series of unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surf ...

and in the MiG-25 fighter jet, presumably to harden the fighter's avionics against radiation. (See

radiation hardening Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation ( particle radiation and high-energy electromagnetic radiation), especially for environ ...

.) This was discovered following the Defection of Viktor Belenko.

Types

* 7586 - First one released, medium mu triode * 7587 - Sharp cutoff tetrode (Anode is top located) * 8056 - triode for low plate voltages * 8058 - triode, with plate cap & grid on shell, for UHF performance * 7895 - 7586 with higher mu * 2CW4 - Same as type 6CW4, but with a 2.1 volt / 450 milliampere heater. Used in television receivers with series heater strings * 6CW4 - high mu triode, most common one in consumer electronics * 6DS4 - remote cutoff 6CW4 * 6DV4 - medium mu, intended as UHF oscillator, shell sometimes gold plated * 8393 - medium mu triode, equivalent of 7586 except heater is 13.5 volts at 60 mA, used in Tektronix equipment. * 13CW4 - same as 6CW4, but with 12.6 Volt / 230 milliampere heater

Dissection of a Nuvistor triode tube

References

External links

The Nuvistor
{{Thermionic valves RCA brands Vacuum tubes