Discharging a Capacitor
Charging a Capacitor
Parity GeneratorClosely Related Articles
Vacuum Diode History Working Principle and Types of Vacuum Diode
PN Junction Diode and its Characteristics
Diode | Working and Types of Diode
Half Wave Diode Rectifier
Full Wave Diode Rectifier
Diode Bridge Rectifier
What is Zener Diode?
Application of Zener Diode
LED or Light Emitting Diode
PIN Photodiode | Avalanche Photodiode
Tunnel Diode and its Applications
Diode Current Equation
Reverse Recovery Time of Diode
Op-amp | Working Principle of Op-amp
Amplifier Gain | Decibel or dB Gain
Integrated Circuits | Types of IC
Regulated Power Supply
Laser | Types and Components of Laser
Mobility of Charge Carrier
What are Photo Electrons?
Electron volt or eV
Energy Quanta | Development of Quantum Physics
Heisenberg Uncertainty Principle
Schrodinger Wave Equation and Wave Function
Cyclotron Basic Construction and Working Principle
Sinusoidal Wave Signal
Common Emitter Amplifier
RC Coupled Amplifier
Wave Particle Duality Principle
MOSFET | Working Principle of p-channel n-channel MOSFET
MOS Capacitor | MOS Capacitance C V Curve
Applications of MOSFET
MOSFET as a Switch
Half Wave Rectifiers
Full Wave Rectifiers
Theory of Semiconductor
Energy Bands of Silicon
Impurities in Semiconductor
Conductivity of Semiconductor
Current Density in Metal and Semiconductor
Intrinsic Silicon and Extrinsic Silicon
P Type Semiconductor
N Type Semiconductor
P N Junction
Bias of P N Junction
Gallium Arsenide Semiconductor
Types of Transistors
Bipolar Junction Transistor
Biasing of BJT
Current Components in a Transistor
Transistor Manufacturing Techniques
Applications of BJT
Transistor as a Switch
Transistor as an Amplifier
n-channel JFET and p-channel JFET
Applications of FET
Tunnel Diode and its Applications
The doping is very high so at absolute zero temperature the Fermi levels lies within the bias of the semiconductors. When no bias is applied any current flows through the junction.
Characteristics of Tunnel DiodeWhen reverse bias is applied the Fermi level of p - side becomes higher than the Fermi level of n-side. Hence, the tunneling of electrons from the balance band of p-side to the conduction band of n-side takes place. With the interments of the reverse bias the tunnel current also increases. When forward junction is a applied the Fermi level of n - side becomes higher that the Fermi level of p - side thus the tunneling of electrons from the n - side to p - side takes place. The amount of the tunnel current is very large than the normal junction current. When the forward bias is increased, the tunnel current is increased up to certain limit. When the band edge of n - side is same with the Fermi level in p - side the tunnel current is maximum with the further increment in the forward bias the tunnel current decreases and we get the desired negative conduction region. When the forward bias is raised further, normal p-n junction current is obtained which is exponentially proportional to the applied voltage. The V - I characteristics of the tunnel diode is given, The negative resistance is used to achieve oscillation and often Ck+ function is of very high frequency frequencies.
Tunnel Diode Symbol
Tunnel Diode ApplicationsTunnel diode is a type of sc diode which is capable of very fast and in microwave frequency range. It was the quantum mechanical effect which is known as tunneling. It is ideal for fast oscillators and receivers for its negative slope characteristics. But it cannot be used in large integrated circuits – that’s why it’s an applications are limited.
When the voltage is first applied current stars flowing through it. The current increases with the increase of voltage. Once the voltage rises high enough suddenly the current again starts increasing and tunnel diode stars behaving like a normal diode. Because of this unusual behavior, it can be used in number of special applications started below.
Oscillator Circuits: Tunnel diodes can be used as high frequency oscillators as the transition between the high electrical conductivity is very rapid. They can be used to create oscillation as high as 5Gz. Even they are capable of creativity oscillation up to 100 GHz in a appropriate digital circuits.
Used in Microwave Circuits: Normal diode transistors do not perform well in microwave operation. So, for microwave generators and amplifiers tunnel diode are. In microwave waves and satellite communication equipments they were used widely, but now a day’s their uses is decreasing rapidly as transistor for working in wave frequency area available in market.
Resistant to Nuclear Radiation: Tunnel diodes are resistant to the effects of magnetic fields, high temperature and radioactivity. That’s why these can be used in modern military equipment. These are used in nuclear magnetic resource machine also. But the most important field of its use satellite communication equipments.
Tunnel Diode OscillatorTunnel diode can make a very stable oscillator circuit when they are coupled to a tuned circuit or cavity, biased at the centre point of negative resistance region. Here is an example of tunnel diode oscillatory circuit.
The tunnel diode is losing coupled to a tunable cavity. By using a short, antenna feed probe placed in the cavity off centre loose coupling is achieved. To increase the stability of oscillation and achieve o/p power over wider bandwidth loose coupling is used. The range of the output power produced is few hundred micro-watts. This is useful for many microwave application. The physical position of the tuner determining the frequency of operation. If the frequency of operation is changed by this method, that is called mechanical tuning. Tunnel diode oscillators can be tuned electronically also.
Tunnel diode oscillators which are meant to be operated at microwave frequencies, generally used some form of transmission lines as tunnel circuit. These oscillators are useful in application that requires a few millwatts of power, example- local oscillators for microwave super electrodyne receiver.
Closely Related Articles Vacuum Diode History Working Principle and Types of Vacuum DiodePN Junction Diode and its CharacteristicsDiode | Working and Types of DiodeDiode CharacteristicsHalf Wave Diode RectifierFull Wave Diode RectifierDiode Bridge RectifierWhat is Zener Diode?Application of Zener DiodeLED or Light Emitting DiodePIN Photodiode | Avalanche PhotodiodeGUNN DiodeVaractor DiodeLaser DiodeSchottky DiodePower DiodesDiode ResistanceDiode Current EquationIdeal DiodeReverse Recovery Time of DiodeDiode TestingMore Related Articles Op-amp | Working Principle of Op-ampAmplifier Gain | Decibel or dB GainIntegrated Circuits | Types of ICRegulated Power SupplyLaser | Types and Components of LaserWork FunctionMobility of Charge CarrierWhat are Photo Electrons? Electron volt or eVEnergy Quanta | Development of Quantum Physics Schottky EffectHeisenberg Uncertainty PrincipleSchrodinger Wave Equation and Wave FunctionCyclotron Basic Construction and Working PrincipleSinusoidal Wave SignalCommon Emitter AmplifierRC Coupled AmplifierDifferential AmplifierWave Particle Duality PrincipleSpace ChargeInverting AmplifierMOSFET | Working Principle of p-channel n-channel MOSFETMOSFET CircuitsMOS Capacitor | MOS Capacitance C V CurveApplications of MOSFETMOSFET as a SwitchMOSFET CharacteristicsPower MOSFETHalf Wave RectifiersFull Wave RectifiersBridge RectifiersClamping CircuitTheory of SemiconductorIntrinsic SemiconductorExtrinsic SemiconductorsEnergy Bands of SiliconDonor and Acceptor Impurities in Semiconductor Conductivity of SemiconductorCurrent Density in Metal and Semiconductor Intrinsic Silicon and Extrinsic SiliconP Type SemiconductorN Type SemiconductorP N Junction Theory Behind P N JunctionForward and Reverse Bias of P N JunctionZener BreakdownAvalanche BreakdownHall Effect Applications of Hall EffectGallium Arsenide SemiconductorSilicon SemiconductorTypes of TransistorsBipolar Junction Transistor or BJTBiasing of Bipolar Junction Transistor or BJTTransistor BiasingTransistor CharacteristicsCurrent Components in a TransistorTransistor Manufacturing TechniquesApplications of Bipolar Junction Transistor or BJT | History of BJTTransistor as a SwitchTransistor as an AmplifierJFET or Junction Field Effect Transistorn-channel JFET and p-channel JFETApplications of Field Effect TransistorDIAC Construction Operation and Applications of DIACTRIAC Construction Operation and Applications of TRIACPhototransistorNew Articles Ring CounterDischarging a CapacitorCharging a CapacitorElectric PotentialParity Generator