What is JFET?

What is JFET?

Junction gate Field-Effect Transistor (JFET) is also known as JUGFET. The JFET is the most simple type of field effect transistor currently in use and has either voltage controlled resistance or an electronically controlled switch. When using a JFET, the electric charge flows in a semiconducting channel that is located between the source and drain terminals. When a bias voltage is applied to the gate terminal, the channel is pinched in order to switch off the electric current. JFET History Jul

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Piezoelectric Transducer

Piezoelectric Transducer

A piezoelectric transducer is a device that converts electricity into mechanical forces or vibrations. Although piezoelectric transducers have other uses, ultrasonic devices require them. Piezoelectric transducers usually converts electricity into vibrations and vibrations into electricity, although this is not always the case. They rely on two phenomena known as “electrostriction” and “the piezoelectric effect.” How Piezoelectric Transducers Work Piezoelectric transducers are made o

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What is an Isolation Transformer?

What is an Isolation Transformer?

An isolation transformer is made of two copper coils that are wound around each other and are each supplied by their own power source. While the term “isolation transformer” technically refers to any transformer, it is specifically a transformer that isolates a circuit from an alternating current. An isolation transformer does this by separating two circuits with an induction loop or decreasing the alternating current's voltage before it reaches the circuit itself. How Isolation Transform

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Zener Diode

Zener Diode

A Zener diode transfers current forward and backward, while traditional diodes are only capable of transferring current forward. Many different electronic systems use Zener diodes to control their circuit's voltage levels. While there are several ways of doing this, Zener diodes provide efficient voltage regulation without damaging the diode itself. How Zener Diodes Work For the most part, a Zener diode acts like a regular diode as current moves in a forward direction in its circuit. However

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Baud Rate

Baud Rate

Named after Emile Baudot, the inventor of the Baudot code for telegraphy, a baud is a unit that is synonymous to symbols per second. Therefore, if there was something with 15 Bd, that would mean that something had 15 symbols per second. Not to be confused with bits per second, the baud -- which, when using the symbol, must follow the SI nomenclature with a capital first letter and a lowercase second letter -- can be any of the many different kinds of symbols while a bit is only 0 or 1. In older

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Retrograde Orbit

Retrograde Orbit

A retrograde orbit is an orbit where the satellite travels in an East to West direction instead of the common West to East orbit. The normal West to East orbits are known as prograde orbits. Retrograde orbits are uncommon due to the much higher velocities necessary for successful launch and the associated higher costs. During a prograde launch, rotational velocity of the Earth is added to the velocity of the launch rocket. In a retrograde launch, the rotational velocity of the Earth is sub

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Ham Radio Software

Ham Radio Software

Ham Radio Software, also known as Amateur Radio Software, refers to computer programs designed exclusively for ham radio equipment. Once thought to be a means of communication between radio enthusiasts, ham radio now coexists with software including data and contest loggers, log books, Morse code tutors, and antenna design aids. In the 21st century there are several software companies that have developed programs specifically for amateur radio enthusiasts. Logging Software: Freedom and Functi

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Ka Band

Ka Band

The Ka band uplink uses frequencies between 27.5GHz and 31Ghz and the downlink uses frequencies between 18.3 and 18.8Ghz and between 19.7 and 20.2Ghz. The Ka band is branch of the K band from the electromagnetic spectrum. The term "Ka-band" is from Kurz-above, which originates from the German phrase "kurz" implying short. Ka band dishes can be much smaller than C band dishes. Ka band dishes vary from 2' to 5' in diameter. Ka band satellites typically transmit with much more power than C ba

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Forward Error Correction (FEC)

Forward Error Correction (FEC)

Forward Error Correction (FEC) is a type of error correction that involves encoding a message in a redundant way, which allows the receiver to reconstruct lost bits without the need for retransmission. How Forward Error Correction Works FEC works by adding “check bits” to the outgoing data stream. Adding more check bits reduces the amount of available bandwidth by increasing the overall block size of the outgoing data, but also enables the receiver to correct for more errors without receiv

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Radio Frequencies and their Corresponding Purposes

Radio Frequencies and their Corresponding Purposes

The Federal Communications Commission (FCC) licenses the frequency spectrum in the United States. Useful charts showing frequency allocations are available from the National Telecommunications and Information Administration (NTIA) at http://www.ntia.doc.gov/osmhome/allochrt.html. This table shows commonly used names for various frequency ranges: Frequency Description 30 - 300 GHz Extremely High Frequency 3 - 30 GHz

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