Semiconductor Electronics

For the logic circuit shown, the truth table is : [figure]

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

For transistor action, which of the following statements is correct?

1. Base, emitter and collector regions should have same size.
2. Both emitter junction as well as the collector junction are forward biased.
3. The base region must be very thin and lightly doped.
4. Base, emitter and collector regions should have same doping concentrations.

The correct Boolean operation represented by the circuit diagram drawn is : [figure]

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

For a p-type semiconductor, which of the following statements is true?

1. Holes are the majority carriers and trivalent atoms are the dopants.
2. Holes are the majority carriers and pentavalent atoms are the dopants.
3. Electrons are the majority carriers and pentavalent atoms are the dopants.
4. Electrons are the majority carriers and trivalent atoms are the dopants.

In the combination of the following gates the output Y can be written in terms of inputs A and B as [figure]

1. A.B
2. A. B + A.B
3. A. B + A.B
4. A + B

In a p-n junction diode, change in temperature due to heating

1. affects only reverse resistance
2. affects only forward resistance
3. does not affect resistance of p-n junction
4. affects the overall V - I characteristics of p-n junction

In the circuit shown in the figure, the input voltage Vi is 20 V, VBE = 0 and VCE = 0. The values of IB, IC and β are given by [figure]

1. IB = 40 , IC = 10 mA, β = 250
2. IB = 25 , IC = 5 mA, β = 200
3. IB = 20 , IC = 5 mA, β = 250
4. IB = 40 , IC = 5 mA, β = 125

The given electrical network is equivalent to [figure]

1. OR gate
2. NOR gate
3. NOT gate
4. AND gate

Which one of the following represents forward bias diode ?

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

In a common emitter transistor amplifier the audio signal voltage across the collector is 3 V. The resistance of collector is 3 k . If current gain is 100 and the base resistance is 2 k , the voltage and power gain of the amplifier is

1. 15 and 200
2. 150 and 15000
3. 20 and 2000
4. 200 and 1000