Vacuum tubes

Koninklijke Philips N.V. (), simply branded Philips, is a Dutch multinational health technology and former consumer electronics company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarters is still in Eindhoven. The company gained its royal honorary title in 1998.

device that controls electric current between electrodes in an evacuated container

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).

device for generating microwaves

thermally induced flow of charge carriers from a surface

device used in electrical engineering

Raytheon is a business unit of RTX Corporation and is a major U.S. defense contractor and industrial corporation with manufacturing concentrations in weapons and military and commercial electronics. Founded in 1922, it merged in 2020 with United Technologies Corporation to form Raytheon Technologies, which changed its name to RTX Corporation in July 2023.

difference of the energy of an electron at rest at infinity and the Fermi energy

defunct American electronics company

thumb|upright|Graphic symbol representing a pentode of the indirectly heated cathode class Electrodes, listed from top to bottom: anode, suppressor grid, screen grid, control grid, cathode A pentode is an electronic device having five electrodes. The term most commonly applies to a three-grid amplifying vacuum tube or thermionic valve that was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode (called a triple-grid amplifier in some literature) was developed from the screen-grid tube or shield-grid tube (a type of tetrode tube) by the addition of a grid between the screen

250px|thumb|right|400 kW klystron used for spacecraft communication at the Canberra Deep Space Communications Complex. This is a spare in storage. thumb|upright=2|5 kW klystron tube used as power amplifier in UHF television transmitter, 1952. When installed, the tube projects through holes in the center of the cavity resonators, with the sides of the cavities making contact with the metal rings on the tube.

electrical component producing a narrow collimated electron beam

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). There are several varieties of tetrodes, the most common being the screen-grid tube and the beam tetrode. In screen-grid tubes and beam tetrodes, the first grid is the control grid and the second grid is the screen grid. In other tetrodes one of the grids is a control grid, while the other may have a variety of functions.

device used to amplify radio frequency signals in the microwave spectrum

thumb|High-power 140 GHz gyrotron for plasma heating in the Wendelstein 7-X fusion experiment, Germany. A gyrotron is a class of high-power linear-beam vacuum tubes that generates millimeter-wave electromagnetic waves by the cyclotron resonance of electrons in a strong magnetic field. Output frequencies range from about 20 to 527 GHz, covering wavelengths from microwave to the edge of the terahertz gap. Typical output powers range from tens of kilowatts to 1–2 megawatts. Gyrotrons can be designed for pulsed or continuous operation. The gyrotron was invented by Soviet scientists at NIRFI, based

thumb|right|A graphical representation of the current and voltage properties of a transistor; the bias is selected so that the operating point permits maximum signal amplitude without distortion.

thumb|Two different types of phototubes A phototube or photoelectric cell is a type of gas-filled or vacuum tube that is sensitive to light. Such a tube is more correctly called a 'photoemissive cell' to distinguish it from photovoltaic or photoconductive cells. Phototubes were previously more widely used but are now replaced in many applications by solid state photodetectors. The photomultiplier tube is one of the most sensitive light detectors, and is still widely used in physics research.

device that captures television images

type of electrode and part of cold cathode fluorescent lamp

vacuum tube with seven electrodes – cathode, anode, and five grids

phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles

thumb|right|300px|

thumb|right|upright|RCA 6DS4 "Nuvistor" triode vacuum tube, ca. 20 mm high and 11 mm in diameter thumb|upright|right|Nuvistor with U.S. dime for scale

vacuum tube device for increasing the intensity of available light

trademark

thumb|Triode Audion [[vacuum tube from 1908. The filament (which was also the cathode) was at the lower left inside the tube, but has burned out and is no longer present. The filament's connecting and supporting wires are visible. The plate is at the middle top, and the grid is the serpentine electrode below it. The plate and grid connections leave the tube at the right.]]

thumb|The Indian Head test pattern was generated by a monoscope.

electronic instrument that measures the resonant frequency of nearby unconnected radio frequency tuned circuits

type of tetrode vacuum tube

vacuum tube used to generate microwaves

vacuum tube electrode directly controlling the anode current

The EL34 is a thermionic vacuum tube of the power pentode type. The EL34 was introduced in 1955 by Mullard, which was owned by Philips. The EL34 has an octal base (indicated by the '3' in the part number) and is found mainly in the final output stages of audio amplification circuits; it was also designed to be suitable as a series regulator by virtue of its high permissible voltage between heater and cathode and other parameters. The American RETMA tube designation number for this tube is 6CA7. The USSR analog was 6P27S (Cyrillic: 6П27C).

electric charge treated as continuously distributed in space

6L6 is the designator for a beam power tube introduced by Radio Corporation of America in April 1936 and marketed for application as a power amplifier for audio frequencies. The 6L6 is a beam tetrode that utilizes formation of a low potential space charge region between the anode and screen grid to return anode secondary emission electrons to the anode and offers significant performance improvements over power pentodes. The 6L6 was the first successful beam power tube marketed. In the 21st century, variants of the 6L6 are manufactured and used in some high fidelity audio amplifiers and musical

thumb|6SN7 vacuum tube dual triode made by Raytheon 6SN7 is a dual triode vacuum tube with an eight-pin octal base. It provides a medium gain (20 dB). The 6SN7 is basically two 6J5 triodes in one envelope.

thumb|upright=0.5|Basic FM quadrature detector circuit using a nonode

electronic device or circuit that produces a precise, fixed voltage

thumb|upright|KN2 "Krytron" switch tube, made by EG&G (about 25 mm tall) The krytron is a cold-cathode gas-filled tube intended for use as a very high-speed switch, somewhat similar to the thyratron. It consists of a sealed glass tube with four electrodes. A small triggering pulse on the grid electrode switches the tube on, allowing a large current to flow between the cathode and anode electrodes. The vacuum version is called a vacuum krytron, or sprytron. The krytron was one of the earliest developments of the EG&G Corporation.

12AX7 (also known as ECC83) is a miniature dual-triode vacuum tube with high voltage gain. Developed around 1946 by RCA engineers in Camden, New Jersey, under developmental number A-4522, it was released for public sale under the 12AX7 identifier on September 15, 1947.

type of electrode.

gas-filled tube for voltage regulation employing either glow or corona discharge

grid (electrode) in a vacuum tube used to suppress the dynatron effect, that occurs due to secondary emission at the anode

The EL84 is a vacuum tube of the power pentode type. It is used in the power-output stages of audio amplifiers, most commonly now in guitar amplifiers, but originally in radios. The EL84 is smaller and more sensitive than the octal 6V6 that was widely used around the world until the 1960s. An interchangeable North American type is the 6BQ5 (the RETMA tube designation name for the EL84).

electrode in the electron gun assembly of some thermionic devices

thumb|upright|12AE10 Compactron tube (a dual pentode), made by GE Compactrons are a type of vacuum tube, which contain multiple electrode structures packed into a single enclosure. They were designed to compete with early transistor electronics and were used in televisions, radios, and similar roles.

electronic instrument for measuring performance of vacuum tubes

A vircator (VIRtual CAthode oscillaTOR) is a microwave generator that is capable of generating brief pulses of tunable, narrow band microwaves at very high power levels. Its application is mainly in the area of electronic warfare, by way of interfering with electronic equipment such as radars or radio equipment.

U.S. manufacturer of diverse electrical equipment

class of electrical battery

Wikimedia list article

high frequency vacuum tube electronic oscillator

Aquadag is a trade name for a water-based colloidal graphite coating commonly used in cathode ray tubes (CRTs). It is manufactured by Acheson Industries, a subsidiary of ICI. The name is a shortened form of "Aqueous Deflocculated Acheson Graphite", but has become a generic term for conductive graphite coatings used in vacuum tubes. Other related products include Oildag, Electrodag and Molydag. Deflocculation refers to the distribution of powdered high purity graphite in an aqueous solution containing approximately 2% to 10% by weight of various Tannic/Gallotannic acid variants and separating t

Serbian company

thumb|6V6 Tube socket|Octal socket basing diagram. 1 - * Unconnected in all versions except for the shell connection of the metal 6V6 2 & 7 - Filament / Heater 3 - Anode / Plate 4 - Grid 2 / Screen Grid 5 - Grid 1 / Control Grid 6 - No connection. Pin normally absent 8 - Cathode & Beam-Forming Plates

a vacuum tube used as a detector for early radio receivers

Television Broadcast Transmitter Power Amplifier

type of klystron for generating low intensity microwaves

280px|thumb|A Sovtek MIG-50 amplifier on top of an SWR Henry 8x8 [[speaker cabinet]] thumb|KT88 vacuum tubes made by Sovtek Sovtek is a brand of vacuum tube owned by Mike Matthews's New Sensor Corporation and manufactured in Saratov, Russia. They are often used in guitar amplification and include versions of the popular 12AX7, EL84, EL34, and 6L6 vacuum tubes. Many of the vacuum-tube amplifiers in modern production are factory-fitted with Sovtek valves. Originally, Sovtek guitar amplifier valves were claimed to have been descendants of earlier wartime Russian-made components and carried blast

electrical connector used for vacuum tubes