Semiconductor Electronics · Question 1

The maximum rated power of the LED is 2 mW and it is used in the circuit with input voltage of 5 V as shown in the figure below. The current through resistance RS is 0.5 mA. The minimum value of the resistance of RS, to ensure that the LED is not damaged is k . [figure]

1. 6
2. 2
3. 4
4. 5

Refer to the logic circuit given below. For two inputs (A=1, B=1) and (A=0, B=1), output (Y) will be . [figure]

1. 1, 0 respectively
2. 0, 1 respectively
3. 0, 0 respectively
4. 1, 1 respectively

For the given logic circuit, which of the following inputs combination will make both LED-1 and LED-2 to glow? [figure]

1. A = 0, B = 1, C = 1
2. A = 1, B = 0, C = 0
3. A = 1, B = 0, C = 1
4. A = 1, B = 1, C = 0

In a semiconductor p-n diode, the doping concentrations on p-side and n-side are 1015 atoms/cm3 and 1018 atoms/cm3, respectively. Which one of the following statements is true ?

1. Widths of depletion region on either side of the interface are equal
2. The depletion region width is more on p-side compared to that in n-side
3. The depletion region width is more on n-side compared to that in p-side
4. No depletion region forms because of unequal doping concentrations on p and n-sides

Two 4 bits binary numbers, A = 1101 and B = 1010 are given in the inputs of a logic circuit shown in figure below. The output (Y) will be : [figure]

1. Y = 1101
2. Y = 0010
3. Y = 0111
4. Y = 1000

Consider a circuit consisting of a capacitor (20 μF), resistor (100 Ω) and two identical diodes as shown in figure. The resistance of diode under forward biasing condition is 10 Ω. The time constant of the circuit is 10-3 s. The value of is . [figure]

1. 2.2
2. 2.0
3. 2.1
4. 2.4

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Choose the correct answer from the options given below :

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
2. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
3. (A) is true but (R) is false
4. (A) is false but (R) is true

A diode has Zener voltage of 10 V and maximum power dissipation of 0.5 W, then the minimum resistance to be used in series with this diode for safety when it is connected to a 25 V power supply is Ω.

For the given circuit (shown in part (A)) the time dependent input voltage vin(t) and corresponding output vo(t) are shown in part (B) and part (C), respectively. Identify the components that are used in the circuit between points X and Y. [figure]

1. [figure]
2. [figure]
3. [figure]
4. [figure]

If X and Y are the inputs, the given circuit works as . [figure]

1. OR gate
2. AND gate
3. NAND gate
4. NOR gate