Why JFET is called a unipolar transistor?

Why JFET is called a unipolar transistor?
by

1 Answer

Answer :

In JFET, the current conduction is either by electrons or holes and controlled by means of an electric field between the gate electrode and the conducting channel of the device, So it is called as a unipolar transistor.
by

Related questions

What is the importance of JFET?

Description : What is the importance of JFET?

Last Answer : A JFET acts like a voltage controlled device i.e. input voltage controls the output current. This is different from ordinary transistor where input current controls the output current. JFET has higher input impedance than that of a conventional transistor.

What is pinch off voltage in JFET?

Description : What is pinch off voltage in JFET?

Last Answer : Pinch off voltage (VP): It is the minimum drain source voltage at which the drain current essentially becomes constant.

What is JFET?

Description : What is JFET?

Last Answer : A junction FET is a three terminal semiconductor device in which current conduction is by one type of carrier (i.e.) electrons or holes.

Why transistor is called current controlled device?

Description : Why transistor is called current controlled device?

Last Answer : The output voltage , current or power is controlled by the input current

Why an ordinary transistor is called bipolar transistor?

Description : Why an ordinary transistor is called bipolar transistor?

Last Answer : Because transistor operation is carried out by both majority and minority carriers

What is the different analysis available to analyze a transistor?

Description : What is the different analysis available to analyze a transistor?

Last Answer : 1. AC analysis 2. DC analysis

How are amplifiers classified according to the transistor configuration?

Description : How are amplifiers classified according to the transistor configuration?

Last Answer : 1. Common emitter amplifier 2. Common base amplifier 3. Common collector amplifier

Explain about the characteristics of a transistor?

Description : Explain about the characteristics of a transistor?

Last Answer : Input characteristics: it is drawn between input voltage & input current while keeping output voltage as constant. Output characteristics: It is drawn between the output voltage &output current while keeping input current as constant.

Explain about the various regions in a transistor?

Description : Explain about the various regions in a transistor?

Last Answer : The three regions are active region saturation region cutoff region.

When does a transistor act as a switch?

Description : When does a transistor act as a switch?

Last Answer : The transistor acts as a switch when it is operated at either cutoff region or saturation region.

Key point for its proper functioning of base region in a transistor depends upon the thickness of the base Why ?

Description : Key point for its proper functioning of base region in a transistor depends upon the thickness of the base Why ?

Last Answer : Base region in a transistor controls the current. The majority charge carriers supplied by the emitter do not combine in the same region due to its thin size and light doping and most of them pass on to the collector. This is the key point for its proper functioning.

why silicon type transistor are more often used than germanium?

Description : why silicon type transistor are more often used than germanium?

Last Answer : because silicon has smaller cutoff current Icbo, small variations in Icbo due to variation in temperature as compared to those in case of germanium.

What are the methods of transistor biasing?

Description : What are the methods of transistor biasing?

Last Answer : 1. fixed bias 2.collector to base bias 3. self bias or voltage divider bias 4. emitter bias

For faster action which transistor is used and why?

Description : For faster action which transistor is used and why?

Last Answer : For faster action NPN Transistor is used .In an NPN transistor, current conduction is mainly by free electron ,whereas in PNP type transistor .it is mainly holes Since electron are more mobile than holes we prefer NPN for faster action as well as high conduction current.

The transistor with the lowest noise figure in the microwave region is a A. MOSFET B. Dual-gate MOSFET C. JFET D. MESFET

Description : The transistor with the lowest noise figure in the microwave region is a A. MOSFET B. Dual-gate MOSFET C. JFET D. MESFET

Last Answer : D. MESFET

What would happen if the base resistor has zero resistance?

Description : What would happen if the base resistor has zero resistance?

Last Answer : If the base resistance is zero, then the base current is very high. Since, we know that the base current is directly proportional to the collector current with the multiplying factor of current ... high. In this time, the transistor operates in saturation region and finally it is being destroyed.

What is a Schmitt trigger?

Description : What is a Schmitt trigger?

Last Answer : Schmitt trigger is a regenerative comparator. It converts sinusoidal input into square wave output. The output of Schmitt trigger swings between upper threshold voltage and lower threshold voltage, the reference voltages of the input waveform.

List the important characteristics of a voltage regulator.

Description : List the important characteristics of a voltage regulator.

Last Answer : The output voltage is fixed at a specified value, The unregulated voltage must be at least 2V more than the regulated voltage.

What is Miller crystal oscillator? Explain its operation.

Description : What is Miller crystal oscillator? Explain its operation.

Last Answer : It is nothing but a Hartley oscillator its feedback Network is replaced by a crystal. Crystal normally generate higher frequency reactance due to the miller capacitance are in effect between the transistor terminal.

Define Piezoelectric effect.

Description : Define Piezoelectric effect.

Last Answer : When applying mechanical energy to some type of crystals called piezoelectric crystals the mechanical energy is converted into electrical energy is called piezoelectric effect.

How to produced 180° phase shift?

Description : How to produced 180° phase shift?

Last Answer : The most common way of achieving this kind of filter is using three identical cascaded resistor capacitor filters, which together produce a phase shift of zero at low frequencies, and 270 degrees at ... phase shift of 60 degrees and the whole filter circuit produces a phase shift of 180 degrees.

What is phase-shift oscillator?

Description : What is phase-shift oscillator?

Last Answer : A phase-shift oscillator is a simple electronic oscillator. It contains an inverting amplifier, and a feedback filter which 'shifts' the phase of the amplifier output by 180 degrees at the oscillation ... 180° at high frequencies, so that the phase shift at the desired oscillation frequency is 180°.

What are LC oscillators?

Description : What are LC oscillators?

Last Answer : Inductive oscillators also known as LC oscillators are built of an tank circuit, which oscillates by charging and discharging a capacitor through an inductor. These oscillators are typically used when a tunable precision frequency source is necessary, such as with radio transmitters and receivers

Types of Harmonic oscillator?

Description : Types of Harmonic oscillator?

Last Answer : A5: There are many ways to implement harmonic oscillators, because there are different ways to amplify and filter. Some of the different circuits are: Hartley oscillator Colpitts oscillator Cross- ... crystal oscillator Phase-shift oscillator RC oscillator (Wien Bridge and "Twin-T")

What is Harmonic oscillator?

Description : What is Harmonic oscillator?

Last Answer : The harmonic, or linear, oscillator produces a sinusoidal output. The basic form of a harmonic oscillator is an electronic amplifier with the output attached to an electronic filter, and the ... around the loop, being filtered and re-amplified until it increasingly resembles the desired signal.

Types of electronic oscillator?

Description : Types of electronic oscillator?

Last Answer : There are two main types of electronic oscillator: the harmonic oscillator and the relaxation oscillator.

Application of electronic oscillator?

Description : Application of electronic oscillator?

Last Answer : An electronic oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave. They are widely used in innumerable electronic devices. Common ... regulate computers and quartz clocks, and the sounds produced by electronic beepers and video games.

What are the conditions for oscillation?

Description : What are the conditions for oscillation?

Last Answer : The total phase shift of an oscillator should be 360 degree. For feedback oscillator it should satisfy Barhausen criterion.

What are the classifications of Oscillators?

Description : What are the classifications of Oscillators?

Last Answer : *Based on wave generated: i. Sinusoidal Oscillator, ii. Non-sinusoidal Oscillator or Relaxation Oscillator Ex: Square wave, Triangular wave, Rectangular wave etc. *According to principle involved ... . Tuned collector base Oscillator iv. Hartley Oscillator v. Colpits Oscillator vi. Clap Oscillator

What is Oscillator circuit?

Description : What is Oscillator circuit?

Last Answer : Oscillators produce a waveform (mostly sine or square waves) of desired amplitude and frequency. They can take input from the output itself. For a complete oscillator circuit we require a feedback device, amplifier and feedback factor.

What is the type of feedback used in an op-amp Schmitt trigger?

Description : What is the type of feedback used in an op-amp Schmitt trigger?

Last Answer : The type of feedback used in an op-amp Schmitt trigger is positive feedback.

What is a monostable Multivibrator?

Description : What is a monostable Multivibrator?

Last Answer : A monostable Multivibrator is a square wave shaping circuit having one stable state and another quasi stable state. It is often referred as single shot Multivibrator. It is also used as gating circuit and delay circuit.

What is Astable Multivibrator?

Description : What is Astable Multivibrator?

Last Answer : Astable Multivibrator is a square wave circuit. It has two quasi stable states. It is also referred as free running Multivibrator.

What is a Multivibrator?

Description : What is a Multivibrator?

Last Answer : Multivibrator is a wave shaping circuit which gives symmetric or asymmetric square wave output. It has two states. They may be either stable or quasi stable depends upon the type of the Multivibrator.

What is meant by voltage follower?

Description : What is meant by voltage follower?

Last Answer : If the output voltage of an op-amp follows the input i.e., if the output voltage is equal to the input voltage it is called as a voltage follower.

Define non-inverting amplifier?

Description : Define non-inverting amplifier?

Last Answer : The input is applied to the non-inverting input terminal and the inverting terminal connected to the ground.

What is the basic building block of an op-amp?

Description : What is the basic building block of an op-amp?

Last Answer : The basic building block of an op-amp is differential amplifier.

List the applications of instrumentation amplifier.

Description : List the applications of instrumentation amplifier.

Last Answer : a. Temperature indicator b. Temperature controller c. Light intensity meters d. Water flow meter c. Thermal conductivity meter f. Analog weight scale

What is the type of feedback employed in the inverting op-amp amplifier?

Description : What is the type of feedback employed in the inverting op-amp amplifier?

Last Answer : Negative feedback is employed in the inverting op-amp amplifier.

What are the DC characteristics of an op-amp?

Description : What are the DC characteristics of an op-amp?

Last Answer : a. input bias current b. Input offset current c .Input offset voltage d. Thermal drift

What are the AC characteristics of an op-amp?

Description : What are the AC characteristics of an op-amp?

Last Answer : a. Frequency response b. Slew rate

What are the methods to improve slew rate?

Description : What are the methods to improve slew rate?

Last Answer : a. The slew rate can be improved with higher closed-loop gain and dc supply voltage. But the slew rate also varies with temperature. i.e., slew rate decreases with increase in temperature. b. Another ... a higher slew rate, op-amp should have either a higher current or a small value of capacitor.

How can the slew rate be made faster?

Description : How can the slew rate be made faster?

Last Answer : The slew rate can be made faster by having a high charging current or a small capacitance value.

Define slew rate?

Description : Define slew rate?

Last Answer : Slew rate can be defined as the maximum rate of change of output voltage of op-amp with respect to time.

What are the methods used in external compensation technique?

Description : What are the methods used in external compensation technique?

Last Answer : a. Dominant-pole compensation b. Pole-zero compensation

What is compensated op-amp?

Description : What is compensated op-amp?

Last Answer : Op-amp, which uses a capacitor internally for compensation, is called a compensated op-amp. This op-amp has a high gain stability and low bandwidth.

What are the two compensating techniques used in frequency compensation?

Description : What are the two compensating techniques used in frequency compensation?

Last Answer : Two types of compensating techniques are used, they are, a. External compensation b. Internal compensation

Define input bias current?

Description : Define input bias current?

Last Answer : It is defined as the average of the currents entering into the input terminals of an op-amp.

Define input offset current?

Description : Define input offset current?

Last Answer : It is defined as the algebraic difference between the current entering the inverting and non-inverting terminal of an op-amp.

Define input offset voltage?

Description : Define input offset voltage?

Last Answer : It is defined as the voltage that must be applied between the input terminals of an op-amp to nullify the output.