DIODO VARICAP. Los diodos varactores o varicap han sido diseñados de manera que su funcionamiento sea similar al de un capacitor y. Diodo Varicap. JC. Johan Cordoba Hoyos. Updated 9 March Transcript. Referencias de imagenes en orden de aparicion y Bibliografia. All following user names refer to dia. Kormoran 87× × ( bytes) Simbolo circuitale di un diodo varicap.
|Published (Last):||10 May 2010|
|PDF File Size:||8.30 Mb|
|ePub File Size:||10.16 Mb|
|Price:||Free* [*Free Regsitration Required]|
File:Varicap – Wikimedia Commons
Views View Edit History.
This reduces the overall capacitance and the capacitance range by half, but has the variicap of reducing the AC component of voltage across each device and has symmetrical distortion should the AC component possess enough amplitude to bias the varicao into forward conduction.
These circuit configurations are quite common in television tuners and electronically tuned broadcast AM and FM receivers, as well as other communications equipment and industrial equipment. Original uploader was Adiasmesquita at pt.
Varactors are operated in a reverse-biased state, so no DC current flows through the device. They are often used in pairs to switch between two different RF sources such as the VHF and UHF bands in a television tuner by supplying them with complementary bias voltages. This work has been released into the public domain by its author, Example at the [[:: The figure shows an example of a cross section of a varactor with the depletion layer formed of a p—n junction.
Generally, the depletion region thickness is proportional to the square root of the applied voltage, and capacitance is inversely proportional to the depletion region thickness. Please help improve this section by adding citations to diovo sources.
This is done to keep costs down — two dual packages could have been used, one for the tank and one for the oscillator, four diodes in all, and this is what was depicted in the application data for the LAN AM radio chip. I, the copyright holder of this work, hereby publish it under the following license:. Dr Tuttle’s Home Page.
The original description page was here. This page was last edited on 13 Novemberat Adobe Photoshop CS Windows. Generally the use of a varicap diode in a circuit requires connecting it to a tuned circuitusually in parallel with any existing capacitance or inductance.
These varkcap were varcap and still are — extensively used in television tuners, whose high carrier frequencies require only small changes in capacitance. Varicap diode Internal structure of a varicap. The following other wikis use this file: Retrieved from ” https: From Wikipedia, the free encyclopedia. The original can be viewed here: September Learn how and when to remove this template message. Varactors are used as voltage-controlled capacitors. The original uploader was Kormoran at Italian Wikipedia.
Retrieved from ” https: The varicap was developed by the Pacific Semiconductor subsidiary of the Ramo Wooldridge Corporation who received a patent for the device in June Separation of grounds is often done to i prevent high-frequency radiation from the low-frequency ground node, and ii prevent DC currents in the AC ground node changing bias and operating points of active devices such as varicaps and transistors.
This depletion layer can also be made of a MOS or a Schottky dioro. In electronicsa varicap diodevaractor diodevariable capacitance diodevariable reactance diode or tuning diode is a type of diode designed to exploit the voltage-dependent capacitance of a reverse-biased p—n junction. Another common configuration uses two back-to-back anode to anode varicap diodes.
Example grants anyone the right to use this work for any purposewithout any viodo, unless such conditions are required by law. Internal structure of a varicap. Date and time of digitizing lun 5 lug Special types of varicap diode exhibiting an abrupt change in capacitance can often be found in consumer equipment such as television tuners, which are used to switch radio frequency signal paths.
The following other wikis use this file: If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The second varicap effectively replaces the blocking capacitor in the first circuit. All following user names refer to it. Popular makeshift varicaps include LEDs,  1NX series rectifier diodes,  Schottky rectifiers and various transistors used with their collector-base junctions reverse biased,  particularly the 2N and BC Sometimes, with very high-Q tuned circuits, an inductor is placed in series with the resistor to increase the source impedance of the control voltage so as not to load the dlodo circuit and decrease its Q.
Early varicap diodes usually required a reverse voltage range of 0—33 v to obtain their full capacitance ranges, which were still quite small, approximately 1—10 pF. Varicaps in various packages.