What is the function of varactor?
Varactor or varicap diodes are used mainly in radio frequency or RF circuits to provide voltage controlled variable capacitance. These electronic componenta can be used in a whole variety of ways where a capacitance level needs to be controlled by a voltage.
What do you mean by varactor?
Definition of varactor : a semiconductor device whose capacitance varies with the applied voltage.
What is VCO circuit?
A voltage-controlled oscillator (VCO) is an oscillator circuit whose frequency can be controlled or varied by a DC input voltage. This type of circuit is also called a voltage-to-frequency converter (VFC). The output waveform from the VCO may be sine, square, or other waveshape depending on the circuit design.
Why are varactor diodes used in oscillator circuits?
A varactor diode is a simple variable capacitor that allows oscillator circuits and other circuits to be easily tuned by applying a voltage. These diodes have a similar structure as a p-n diode; the structure of a varactor diode is rather simple and illustrates its power as a component with nonlinear reactance.
What is meant by varactor diode?
Varactor Diode is a reverse-biased p-n junction diode, whose capacitance can be varied electrically. As a result these diodes are also referred to as varicaps, tuning diodes, voltage variable capacitor diodes, parametric diodes, and variable capacitor diodes.
What is PLL and VCO?
A phase-locked loop (PLL) circuit is a feedback system that combines a voltage controlled oscillator (VCO) and a phase detector in such a way that the oscillator signal tracks an applied frequency or phase modulated signal with the correct frequency and phase.
What is the symbol of varactor diode?
Varactor Diode Formulae
| Capacitance of Varactor Diode | C j = C K ( V b − V ) m |
|---|---|
| Quality factor of the Varactor Diode | Q = F f |
Which is name for varactor diode?
varicap diode
In electronics, a varicap diode, varactor diode, variable capacitance diode, variable reactance diode or tuning diode is a type of diode designed to exploit the voltage-dependent capacitance of a reverse-biased p–n junction.
What is varactor diode and tunnel diode?
A Tunnel diode is a heavily doped p-n junction diode in which the electric current decreases as the voltage increases. In tunnel diode, electric current is caused by “Tunneling”. The tunnel diode is used as a very fast switching device in computers. It is also used in high-frequency oscillators and amplifiers.
What is the function of varactor in oscillator circuit?
The varactor is used in this oscillator circuit to vary the frequency of the waveforms produced. This oscillator circuit produces waveforms of different frequencies. When the voltage is increased, the waveforms vibrate much faster. When the voltage is decreased, the waveforms decrease in vibrations.
How is a varactor used in a tuning circuit?
The reverse voltage may be applied via a tuning potentiometer, which acts to change the overall frequency of an oscillator. Therefore, varactors have widespread use in tuning circuits where a change in capacitance tunes the circuit. To see how varactors are used in tuning circuits, see Varactor Tuning Circuit.
What is a varactor and how does it work?
A varactor (which is a shortened form of variable reactor) is simply a pn -junction diode that has been engineered to maximize the value and range of junction capacitance with the goal of applying the device as a voltage controlled capacitor in various tuned circuits such as filters and oscillators.
What is a varactor diode AC equivalent circuit?
Varactor diode AC equivalent circuit. An important characteristic of any varactor diode is its Q factor. This is particularly important in tuned oscillator applications as a high Q varactor will result in a higher Q tank circuit which will in turn reduce the phase noise produced by the oscillator.
