Advertisements
Advertisements
Question
Two identical p-n junction may be connected in series with a battery in three ways. The potential difference across the two p-n junctions are equal in
Options
circuit 1 and circuit 2
circuit 2 and circuit 3
circuit 3 and circuit 1
circuit 1 only.
Advertisements
Solution
circuit 2 and circuit 3
In circuit 1, one diode is forward biassed and the other diode is reverse biassed.
The forward-biassed diode offers zero resistance (ideally) to the current flow, so it can be replaced by a short circuit. The voltage drop across the first diode will be zero. The second diode is reverse biassed, so it can be replaced by an open circuit; hence, the voltage drop across this diode will be maximum.
In circuit 2, both the diodes are forward biassed, so they can be replaced by short circuits; hence, the voltage drop across both of them will be minimum and equal.
In circuit 3, both the diodes are reverse biassed, so both can be replaced by open circuits; hence, the voltage drop across both of them will be maximum and equal.
APPEARS IN
RELATED QUESTIONS
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.
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.
When a p-type impurity is doped in a semiconductor, a large number of holes are created, This does not make the semiconductor charged. But when holes diffuse from the p-side to the n-side in a p-n junction, the n-side gets positively charged. Explain.
The drift current in a p-n junction is
Diffusion current in a p-n junction is greater than the drift current in magnitude
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.
When a p-n junction is reverse-biased, the current becomes almost constant at 25 µA. When it is forward-biased at 200 mV, a current of 75 µA is obtained. Find the magnitude of diffusion current when the diode is
(a) unbiased,
(b) reverse-biased at 200 mV and
(c) forward-biased at 200 mV.
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?
Calculate the current through the circuit and the potential difference across the diode shown in figure. The drift current for the diode is 20 µA.
What are the readings of the ammeters A1 and A2 shown in figure. Neglect the resistance of the meters.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
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.)
Draw the current-voltage characteristics for the device show in figure between the terminals A and B.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
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 __________ .
Answer in detail.
Discuss the effect of external voltage on the width of depletion region of a p-n junction.
The depletion layer in the p-n junction diode is caused by ______.
The formation of the depletion region in a p-n junction diode is due to ______.
For an ideal diode, in forward and reverse biased condition the resistance is respectively ______.
