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Encyclopedia > Gunn diode
A rough approximation of the VI curve for a Gunn diode, showing the negative differential resistance region
A rough approximation of the VI curve for a Gunn diode, showing the negative differential resistance region

A Gunn diode, also known as a transferred electron device (TED) is a form of diode used in high-frequency electronics. It is somewhat unusual in that it consists only of N-doped semiconductor material, whereas ordinary diodes consist of both P and N-doped regions. In the Gunn diode, three regions exist: two of them are heavily N-doped on each terminal, with a thin layer of lightly doped material in between. When a voltage is applied to the device, the electrical gradient will be largest across the thin middle layer. Eventually, this layer starts to conduct, reducing the gradient across it, preventing further conduction. In practice, this means a Gunn diode has a region of negative differential resistance. Image File history File links Download high resolution version (900x900, 41 KB) Negative differential resistance plot, such as in a Gunn diode. ... Image File history File links Download high resolution version (900x900, 41 KB) Negative differential resistance plot, such as in a Gunn diode. ... Types of diodes In electronics, a diode is a component that restricts the direction of movement of charge carriers. ... The field of electronics is the study and use of systems that operate by controlling the flow of electrons or other electrically charged particles in devices such as thermionic valves and semiconductors. ... In semiconductor production, doping refers to the process of intentionally introducing impurities into an intrinsic semiconductor in order to change its electrical properties. ... A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ... In electrical circuits, static resistance is the ratio of the voltage across a circuit element to the current through it. ...


The negative resistance, combined with the timing properties of the intermediate layer, allows construction of an RF relaxation oscillator simply by applying a suitable direct current through the device. The oscillation frequency is determined partly by the properties of the thin middle layer, but can be adjusted by external factors. Gunn diodes are therefore used to build oscillators in the 10 GHz and higher (THz) frequency range, where a resonant cavity is usually added to control frequency. The resonator can be based on a waveguide, coaxial cavity, YIG resonator, etc. Tuning is done mechanically, by adjusting the parameters of the resonator, or in case of YIG resonators by electric current. Rough plot of Earths atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including radio waves. ... A relaxation oscillator is an oscillator in which a capacitor is charged gradually and then discharged rapidly. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ... A terahertz is 1012 hertz or a thousand gigahertz, a measure of frequency. ... A cavity resonator uses resonance to amplify a wave. ... A resonator is device or part that vibrates with and amplify waves. ... To meet Wikipedias quality standards and appeal to a wider international audience, this article may require cleanup. ...


Gallium arsenide Gunn diodes are made for frequencies up to 200 GHz, gallium nitride materials can reach up to 3 terahertz. This article is about the chemical compound. ... Gallium nitride (GaN) is a wide bandgap semiconductor material used in optoelectronic, high-power and high-frequency devices. ... A terahertz (THz) is 1012 hertz or a thousand gigahertz, a measure of frequency. ...


External links

  • A Gunn diode relaxation oscillator
  • Negative resistance oscillators
  • Gunn diode hot electron injectors: graded gap injector and resonant tunneling injector

  Results from FactBites:
 
Radio-Electronics.Com :: Summary of the Gunn Diode (866 words)
Gunn diodes are a form of semiconductor component able to operate at frequencies from a few Gigahertz up to frequencies in the region of 100 GHz.
The frequency of the signal generated by a Gunn diode is chiefly set by the thickness of the active region.
The Gunn diode is placed into the cavity along with the YIG which has the effect of reducing the effective size of the cavity.
  More results at FactBites »

 
 

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