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प्रश्न
Diffusion current in a p-n junction is greater than the drift current in magnitude
पर्याय
if the junction is forward-biased
if the junction is reverse-biased
if the junction is unbiased
in no case.
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उत्तर
if the junction is forward-biassed
In the forward biassing of a p−n junction, the positive terminal of the battery is connected to the p side of the p−n junction and the negative terminal of the battery is connected to the n side of the p−n junction. As a result, electrons in the n side of the p−njunction are repelled by the negative terminal of the battery and move to the p side, where the positive terminal of the battery attracts the electrons. Similarly, holes from the p side of the p−n junction are repelled by the positive terminal of the battery and move to the n side, where the negative terminal of the battery attracts the holes. Thus, they give diffusion current across the p−n junction.
In case of reverse biassing, no conduction takes place across the junction because of the diffusion of majority carriers. Hence, there is no diffusion current.
If the junction is unbiased, then diffusion current is initially maximum. But at equilibrium, diffusion current becomes equal to drift current.
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संबंधित प्रश्न
Explain briefly with the help of necessary diagrams, the forward biasing of a p-n junction diode. Also draw characteristic curves.
Draw a circuit diagram to study the input and output characteristics of an n-p-n transistor in its common emitter configuration. Draw the typical input and output characteristics.
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.
The drift current in a reverse-biased p-n junction is increased in magnitude if the temperature of the junction is increased. Explain this on the basis of creation of hole-electron pairs.
The drift current in a p-n junction is
A hole diffuses from the p-side to the n-side in a p-n junction. This means that
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.
In a p-n junction,
(a) new holes and conduction electrons are produced continuously throughout the material
(b) new holes and conduction electrons are produced continuously throughout the material except in the depletion region
(c) holes and conduction electrons recombine continuously throughout the material
(d) holes and conduction electrons recombine continuously throughout the material except in the depletion region.
The potential barrier existing across an unbiased p-n junction is 0.2 volt. What minimum kinetic energy a hole should have to diffuse from the p-side to the n-side if (a) the junction is unbiased, (b) the junction is forward-biased at 0.1 volt and (c) the junction is reverse-biased at 0.1 volt?
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?
Find the current through the resistance R in figure if (a) R = 12Ω (b) R = 48Ω.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
Find the equivalent resistance of the network shown in figure between the points A and B.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
When the base current in a transistor is changed from 30µA to 80µA, the collector current is changed from 1.0 mA to 3.5 mA. Find the current gain β.
An AC source is connected to a diode and a resistor in series. Is the current thorough the resistor AC or DC?
If in a p-n junction diode, a square input signal of 10 V is applied as shown Then the output signal across RL will be ______
p-n junction diode is formed
Zener breakdown occurs in a p-n junction having p and n both:
