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प्रश्न
Explain briefly with the help of necessary diagrams, the forward biasing of a p-n junction diode. Also draw characteristic curves.
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उत्तर
p-n junction diode under forward bias
p-side is connected to positive terminal and n-side to the negative terminal.
Applied voltage drops across the depletion region.
Direction of applied voltage (V) is opposite to the build in potential (V0).
As the depletion layer width decreases, the barrier height is reduced.
Effective barrier height under forward bias is (V0 − V).
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Electron in n-region moves towards the p-n junction and holes in p-region move towards the junction. The width of the depletion layer decreases and hence, it offers less resistance.
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Diffusion of majority carriers takes place across the junction.
This leads to forward current.
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संबंधित प्रश्न
In a p-n junction diode, the current I can be expressed as
I = `"I"_0 exp ("eV"/(2"k"_"BT") - 1)`
where I0 is called the reverse saturation current, V is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, kBis the Boltzmann constant (8.6×10−5 eV/K) and T is the absolute temperature. If for a given diode I0 = 5 × 10−12 A and T = 300 K, then
(a) What will be the forward current at a forward voltage of 0.6 V?
(b) What will be the increase in the current if the voltage across the diode is increased to 0.7 V?
(c) What is the dynamic resistance?
(d) What will be the current if reverse bias voltage changes from 1 V to 2 V?
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.
Diffusion current in a p-n junction is greater than the drift current in magnitude
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, 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?
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?
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 ______
Zener breakdown occurs in a p-n junction having p and n both:
During the formation of a p-n junction ______.
