# The current-voltage characteristic of an ideal $$\mathrm{p \text{-}n}$$ junction diode is given by the graph as shown in the following figure:                 This diode is connected with a resistance of $$5~\Omega$$ in series with it as shown below:                     Which of the following shows the dependence of the voltage $$V_{AB}$$ and the current $$i$$, when the diode is forward-biased? ($$V_{AB}$$ in volt, $$i$$ in ampere)   1. $$V_{A B}=i\cdot5+0.6$$ 2. $$V_{A B}=i\cdot5-0.6$$ 3. $$V_{A B}=i\cdot5+(0.6-5)$$ 4. $$V_{A B}=i\cdot5+\left(0.6+5\right)$$

Subtopic: Â PN junction |
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The voltage $$V_{AB}=20~V$$ at its peak value, and is sinusoidal in time. The current $$i$$ (in amperes), when plotted as a function of time, is given by:
(Consider the diodes as ideal.)
 1 2 3 4

Subtopic: Â PN junction |
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For the above circuit, the applied voltage $$V(t)$$ is periodic and linear, and is shown by the waveform below:

The current flowing through $$R_2$$ varies as:

 1 2 3 4
Subtopic: Â Applications of PN junction |
Â 55%
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The dynamic resistance of a diode is given by $$R=\dfrac{26}{i(mA)}~\Omega,$$ where $$i$$ is the diode current.
 Statement I: If the current through the diode increases, then the dynamic resistance decreases. Statement II: If the temperature of the diode is increased, with the potential difference fixed, the dynamic resistance decreases.

 1 Statement I is incorrect and Statement II is correct. 2 Both Statement I and Statement II are correct. 3 Both Statement I and Statement II are incorrect. 4 Statement I is correct and Statement II is incorrect.
Subtopic: Â PN junction |
Â 68%
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A Zener diode when used as a voltage regulator is connected:
 i. in forward bias ii. in reverse bias iii. in parallel with the load iv. in series with the load
Choose the correct option:
 1 (i) and (ii) are correct 2 (ii) and (iii) are correct 3 only (i) is correct 4 only (iv) is correct
Subtopic: Â Applications of PN junction |
Â 88%
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The two inputs ($$A$$) and ($$B$$) of a logic circuit are shown along with the output ($$Y$$) as functions of time. The 'highs' represent logic $$1$$ and the 'lows' represents logic $$0$$. The correct truth table for this circuit is:

1.
 $$A$$ $$B$$ $$Y$$ $$0$$ $$0$$ $$0$$ $$0$$ $$1$$ $$0$$ $$1$$ $$0$$ $$1$$ $$1$$ $$1$$ $$0$$
2.
 $$A$$ $$B$$ $$Y$$ $$0$$ $$0$$ $$0$$ $$0$$ $$1$$ $$1$$ $$1$$ $$0$$ $$0$$ $$1$$ $$1$$ $$0$$
3.
 $$A$$ $$B$$ $$Y$$ $$0$$ $$0$$ $$1$$ $$0$$ $$1$$ $$0$$ $$1$$ $$0$$ $$0$$ $$1$$ $$1$$ $$1$$
4.
 $$A$$ $$B$$ $$Y$$ $$0$$ $$0$$ $$0$$ $$0$$ $$1$$ $$1$$ $$1$$ $$0$$ $$1$$ $$1$$ $$1$$ $$0$$
Subtopic: Â Logic gates |
Â 79%
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Zener diode is not used for:
1. oscillatory circuit
2. current amplification
3. voltage amplification
4. all of the above
Subtopic: Â Applications of PN junction |
Â 70%
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Given below are two statements:
 Assertion (A): The resistance of a photodiode decreases when light having photons of sufficient energy is incident on it. Reason (R): When energetic photons fall on the $$\mathrm{p\text{-}n}$$ junction of a photodiode, electron-hole pairs are created due to the breaking of the valence bonds.

 1 (A) is True but (R) is False. 2 (A) is False but (R) is True. 3 Both (A) and (R) are True and (R) is the correct explanation of (A). 4 Both (A) and (R) are True but (R) is not the correct explanation of (A).
Subtopic: Â Applications of PN junction |
Â 70%
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In the circuit shown in the diagram given below, R is a small resistor, Vi is the input voltage between A & B while Vis the output voltage between C & D.

Consider the following two statements and mark the correct option.
(I) If Vi > 2 V, then Vo = Vi
(II) If Vi < 2 V, then Vo = 2 V
1. I is true.
2. II is true.
3. I and II are both true.
4. I and II are both false.
Subtopic: Â PN junction |
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In the following figure, the diodes which are forward biased are:
 (a) (b) (c) (d)

1. (a), (b) and (d)
2. (c) only
3. (a) and (c)
4. (b) and (d)

Subtopic: Â PN junction |
Â 83%
From NCERT
AIPMT - 2011
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