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प्रश्न
The drift current in a p-n junction is
विकल्प
from the n-side to the p-side
from the p-side to the n-side
from the p-side to the side if the junction is forward-biased and the opposite direction if it is reverse-biased
from the p-side to the n-side if the junction is forward-baised and in the opposite direction if it is reverse-biased.
उत्तर
from the n-side to the p-side
After the diffusion of majority charge carriers across a p‒n junction, an electric field is set up because of the accumulation of immobile ions at the junction. These further oppose the motion of majority charge carriers across the junction. As a result, electrons from the p region start moving to the n region and holes from the n region start moving to the p region. This constitutes the drift current. As the direction of the current is opposite to the direction of the motion of the electrons, the direction of the drift current is from the n side to the p side.
In forward biasing, there is no movement of electrons from the p region to the n region and of holes from the n region to the p region. Hence, there is not drift current.
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संबंधित प्रश्न
In an unbiased p-n junction, holes diffuse from the p-region to n-region because ______.
Explain briefly with the help of necessary diagrams, the forward biasing of a p-n junction diode. Also draw characteristic curves.
Explain, with the help of a circuit diagram, the working of a photo-diode. Write briefly how it is used to detect the optical signals.
Mention the important considerations required while fabricating a p-n junction diode to be used as a Light Emitting Diode (LED). What should be the order of band gap of an LED if it is required to emit light in the visible range?
How is a zener diode fabricated so as to make it a special purpose diode? Draw I-V characteristics of zener diode and explain the significance of breakdown voltage.
Explain briefly, with the help of a circuit diagram, how a p-n junction diode works as a half wave rectifier.
In a p-n junction with open ends,
(a) there is no systematic motion of charge carries
(b) holes and conduction electrons systematically go from the p-side to n-side and from the n-side to p-side respectively
(c) there is no net charge transfer between the two sides
(d) there is a constant electric field near the junction.
A semiconducting device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops to almost zero. the device may be
(a) an intrinsic semiconductor
(b) a p-type semiconductor
(c) an n-type semiconductor
(d) a p-n junction
In a p.n junction, the depletion region is 400 nm wide and an electric field of 5 × 105 V m−1 exists in it. (a) Find the height of the potential barrier. (b) What should be the minimum kinetic energy of a conduction electron which can diffuse from the n-side to the p-side?
In a p-n junction, a potential barrier of 250 meV exists across the junction. A hole with a kinetic energy of 300 meV approaches the junction. Find the kinetic energy of the hole when it crosses the junction if the hole approached the junction (a) from the p-side and (b) from the n-side.
The current−voltage characteristic of an ideal p-n junction diode is given by \[i = i_0 ( e^{eV/KT} - 1)\] where, the drift current i0 equals 10 µA. Take the temperature T to be 300 K. (a) Find the voltage V0 for which \[e^{eV/kT} = 100 .\]One can neglect the term 1 for voltages greater than this value. (b) Find an expression for the dynamic resistance of the diode as a function of V for V > V0. (c) Find the voltage for which the dynamic resistance is 0.2 Ω.
(Use Planck constant h = 4.14 × 10-15 eV-s, Boltzmann constant k = 8·62 × 10-5 eV/K.)
Consider a p-n junction diode having the characteristic \[i - i_0 ( e^{eV/kT} - 1) \text{ where } i_0 = 20\mu A\] . The diode is operated at T = 300 K . (a) Find the current through the diode when a voltage of 300 mV is applied across it in forward bias. (b) At what voltage does the current double?
Each of the resistance shown in figure has a value of 20 Ω. Find the equivalent resistance between A and B. Does it depend on whether the point A or B is at higher potential?
Find the current through the battery in each of the circuits shown in figure.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
A load resistor of 2kΩ is connected in the collector branch of an amplifier circuit using a transistor in common-emitter mode. The current gain β = 50. The input resistance of the transistor is 0.50 kΩ. If the input current is changed by 50µA. (a) by what amount does the output voltage change, (b) by what amount does the input voltage change and (c) what is the power gain?
An AC source is connected to a diode and a resistor in series. Is the current thorough the resistor AC or DC?
A diode, a resistor and a 50 Hz AC source are connected in series. The number of current pulses per second through the resistor is __________ .
Choose the correct option.
Current through a reverse-biased p-n junction increases abruptly at:
Answer in detail.
Discuss the effect of external voltage on the width of depletion region of a p-n junction.
The formation of the depletion region in a p-n junction diode is due to ______.
