Pentode transistor

Last updated

A pentode transistor is any transistor having five active terminals.

Transistor semiconductor device used to amplify and switch electronic signals and electrical power

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.


Early pentode transistors

One early pentode transistor was developed in the early 1950s as an improvement over the point-contact transistor.

Point-contact transistor first type of solid-state electronic transistor ever constructed

The point-contact transistor was the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. They worked in a group led by physicist William Shockley. The group had been working together on experiments and theories of electric field effects in solid state materials, with the aim of replacing vacuum tubes with a smaller device that consumed less power.

Pentode field-effect transistors having 3 gates, similar to vacuum tube pentodes have also been described [1]

Modern pentode transistors

Integrated injection logic class of digital circuits

Integrated injection logic (IIL, I2L, or I2L) is a class of digital circuits built with multiple collector bipolar junction transistors (BJT). When introduced it had speed comparable to TTL yet was almost as low power as CMOS, making it ideal for use in VLSI (and larger) integrated circuits. Although the logic voltage levels are very close (High: 0.7V, Low: 0.2V), I2L has high noise immunity because it operates by current instead of voltage. I2L was developed in 1971 by Siegfried K. Wiedmann and Horst H. Berger who originally called it merged-transistor logic (MTL).

Related Research Articles


Compactrons are a type of thermionic valve, or 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.

In electronics, a logic gate is an idealized or physical device implementing a Boolean function; that is, it performs a logical operation on one or more binary inputs and produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device.

A semiconductor device is an electronic component that exploits the electronic properties of semiconductor material, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced vacuum tubes in most applications. They use electrical conduction in the solid state rather that the gaseous state or thermionic emission in a vacuum.

JFET type of field-effect transistor

The junction gate field-effect transistor is one of the simple type of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically-controlled switches, amplifiers, or voltage-controlled resistors.

Bipolar junction transistor transistor that uses both electron and hole charge carriers.In contrast,unipolar transistors such as field-effect transistors,only use one kind of charge carrier.For their operation,BJTs use 2 junctions between 2 semiconductor types,n-type and p-type

A bipolar junction transistor is a type of transistor that uses both electron and hole charge carriers. In contrast, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier. For their operation, BJTs use two junctions between two semiconductor types, n-type and p-type.

CMOS technology for constructing integrated circuits

Complementary metal–oxide–semiconductor (CMOS) is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits. CMOS technology is also used for several analog circuits such as image sensors, data converters, and highly integrated transceivers for many types of communication. Frank Wanlass invented CMOS in 1963 while at Fairchild Semiconductor and was granted US patent 3,356,858 in 1967.

A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch.

Gallium arsenide chemical compound

Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic. It is a III-V direct bandgap semiconductor with a zinc blende crystal structure.

Emitter-coupled logic high-speed integrated circuit bipolar transistor logic family

In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family. ECL uses an overdriven BJT differential amplifier with single-ended input and limited emitter current to avoid the saturated region of operation and its slow turn-off behavior. As the current is steered between two legs of an emitter-coupled pair, ECL is sometimes called current-steering logic (CSL), current-mode logic (CML) or current-switch emitter-follower (CSEF) logic.

Resistor–transistor logic (RTL) is a class of digital circuits built using resistors as the input network and bipolar junction transistors (BJTs) as switching devices. RTL is the earliest class of transistorized digital logic circuit used; other classes include diode–transistor logic (DTL) and transistor–transistor logic (TTL). RTL circuits were first constructed with discrete components, but in 1961 it became the first digital logic family to be produced as a monolithic integrated circuit. RTL integrated circuits were used in the Apollo Guidance Computer, whose design was begun in 1961 and which first flew in 1966.

In computer engineering, a logic family may refer to one of two related concepts. A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compatible logic levels and power supply characteristics within a family. Many logic families were produced as individual components, each containing one or a few related basic logical functions, which could be used as "building-blocks" to create systems or as so-called "glue" to interconnect more complex integrated circuits. A "logic family" may also refer to a set of techniques used to implement logic within VLSI integrated circuits such as central processors, memories, or other complex functions. Some such logic families use static techniques to minimize design complexity. Other such logic families, such as domino logic, use clocked dynamic techniques to minimize size, power consumption and delay.

Organic field-effect transistor

An organic field-effect transistor (OFET) is a field-effect transistor using an organic semiconductor in its channel. OFETs can be prepared either by vacuum evaporation of small molecules, by solution-casting of polymers or small molecules, or by mechanical transfer of a peeled single-crystalline organic layer onto a substrate. These devices have been developed to realize low-cost, large-area electronic products and biodegradable electronics. OFETs have been fabricated with various device geometries. The most commonly used device geometry is bottom gate with top drain and source electrodes, because this geometry is similar to the thin-film silicon transistor (TFT) using thermally grown SiO2 as gate dielectric. Organic polymers, such as poly(methyl-methacrylate) (PMMA), can also be used as dielectric.

Pentode electronic device having five active electrodes; the term most commonly applies to a three-grid amplifying vacuum tube

A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid amplifying vacuum tube, which was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode consists of an evacuated glass envelope containing five electrodes in this order: a cathode heated by a filament, a control grid, a screen grid, a suppressor grid, and a plate (anode). The pentode was developed from the tetrode tube by the addition of a third grid, the suppressor grid. This served to prevent secondary emission electrons emitted by the plate from reaching the screen grid, which caused instability and parasitic oscillations in the tetrode. The pentode is closely related to the beam tetrode. Pentodes were widely used in industrial and consumer electronic equipment such as radios and televisions until the 1960s, when they were replaced by transistors. Their main use now is in high power industrial applications such as radio transmitters. The obsolete consumer tubes are still used in a few legacy and specialty vacuum tube audio devices.

Electronic symbol pictogram used to represent various electrical and electronic devices in a schematic diagram of an electrical or electronic circuit

An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions.

Multigate device type of MOS field-effect transistor with more than one gate

A multigate device or multiple-gate field-effect transistor (MuGFET) refers to a MOSFET that incorporates more than one gate into a single device. The multiple gates may be controlled by a single gate electrode, wherein the multiple gate surfaces act electrically as a single gate, or by independent gate electrodes. A multigate device employing independent gate electrodes is sometimes called a multiple-independent-gate field-effect transistor (MIGFET).

A tetrode transistor is any transistor having four active terminals.

A transistor is a semiconductor device with at least three terminals for connection to an electric circuit. The vacuum-tube triode, also called a (thermionic) valve, was the transistor's precursor, introduced in 1907.

Field-effect transistor transistor that uses an electric field to control the electrical behaviour of the device. FETs are also known as unipolar transistors since they involve single-carrier-type operation

The field-effect transistor (FET) is an electronic device which uses an electric field to control the flow of current. FETs are 3-terminalled devices, having a source, gate, and drain terminal. FETs control the flow of current by the application of a voltage to the gate terminal, which in turn alters the conductivity between the drain and source terminals.


  1. US Patent 4,104,673 August 1,1978 [ permanent dead link ]