A balun /ˈbælʌn/ (from "balanced to unbalanced", originally, but now derived from "balancing unit") is an electrical device that allows balanced and unbalanced lines to be interfaced without disturbing the impedance arrangement of either line. A balun can take many forms and may include devices that also transform impedances but need not do so. Sometimes, in the case of transformer baluns, they use magnetic coupling but need not do so. Common-mode chokes are also used as baluns and work by eliminating, rather than rejecting, common mode signals.
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Balun in the context of UTR-2
The Ukrainian T-shaped Radio telescope, second modification (official abbreviation UTR-2) is the world's largest low-frequency radio telescope at decametre wavelengths. It was completed in 1972 near the village of Hrakovo (49°38′N 36°56′E / 49.633°N 36.933°E), 15 km west-south-west from Shevchenkove, Ukraine. The telescope is operated by the Institute of Radio Astronomy of the Ukrainian Academy of Sciences.
The UTR-2 consists of an array of 2040 dipole elements in two arms each containing 6 rows of elements, oriented in a T shape: a north–south arm consisting of 1440 elements covering an area of 1800×60 meters, and an east–west arm consisting of 600 elements covering an area of 900×60 meters. The basic element is a broadband cage dipole 1.8 m in diameter and 8 m long made of galvanized steel wire, mounted 3.5 m above the ground, with a balun to connect it to the transmission line. The dipoles are all oriented along the east–west axis, with the spacing between rows of 7.5 m in east–west direction and 9 m in north–south. It has a total area of 150,000 square metres (1,600,000 sq ft), and a resolution of about 40 arcminutes at the middle frequency 16.7 MHz. The operating frequency range is 8–33 MHz. The sensitivity is about 10 mJy.
View the full Wikipedia page for UTR-2Balun in the context of Integrated passive devices
Integrated passive devices (IPDs), also known as integrated passive components (IPCs) or embedded passive components (EPC), are electronic components where resistors (R), capacitors (C), inductors (L)/coils/chokes, microstriplines, impedance matching elements, baluns or any combinations of them are integrated in the same package or on the same substrate. Sometimes integrated passives can also be called as embedded passives, and still the difference between integrated and embedded passives is technically unclear. In both cases passives are realized in between dielectric layers or on the same substrate.
The earliest form of IPDs are resistor, capacitor, resistor-capacitor (RC) or resistor-capacitor-coil/inductor (RCL) networks. Passive transformers can also be realised as integrated passive devices like by putting two coils on top of each other separated by a thin dielectric layer. Sometimes diodes (PN, PIN, zener etc.) can be integrated on the same substrate with integrated passives specifically if the substrate is silicon or some other semiconductor like gallium arsenide (GaAs).
View the full Wikipedia page for Integrated passive devices