Semiconductor Electronics: Materials, Devices and Simple Circuits

The output of given logic circuit is

• A . (B + C)

• A . (B . C)

• (A + B) . (A + C)

• A + B + C

Copper and Germanium are cooled from room temperature to 100 K. Then, the resistance of

• germanium increases, copper increases

• germanium decreases, copper increases

• germanium decreases, copper decreases

• germanium increases, copper decreases

For a transistor, β = 100. The value of α is

• 0.01

• 1.01

• 0.99

• 100

The following truth table with A and B as inputs is for ....... gate

• NOR

• AND

• OR

• XOR

In which of the following statements, the obtained impure semiconductor is of p-type ?

• Germanum is doped with bismuth

• Silicon is doped with antimony

• Germanium is doped with gallium

• Silicon is doped with phosphorus

The width of the depletion region in a p-n junction diode is

• increased by reverse bias

• increased by forward bias

• decreased by reverse bias

• independent of the bias voltage

When the transistor is used as an amplifier

• Emitter-base junction must be reverse biased, Collector-base junction must be forward

• Emitter-base junction must be forward biased, Collector-base Junction must be forward biased

• Emitter-base junction must be reverse biased, Collector-base junction must be reverse biased

• Emitter-base junction must be forward biased, Collector-base junction must be reverse biased

The output of an OR gate is connected to both the inputs of a NAND gate. The combination will serve as

• AND gate

• NOT gate

• NAND gate

• NOR gate

In n-type semiconductor, electrons are majority charge carriers but it does not show any negative charge. The reason is

• electrons are stationary

• electrons neutralize with holes

• mobility of electrons is extremely small

• atom is electrically neutral

For the given digital circuit, write the truth table and identify the logic gate it represents

• OR gate

• NOR gate

• NAND gate

• AND gate