Semiconductor Electronics: Materials, Devices and Simple Circuits

If α-current gain of a transistoris 0.98. What is the value of β-current gain of the transistor ?

• 0.49

• 49

• 4.9

• 5

A tuned amplifier circuit is used to generate a carrier frequency of 2 MHz for the amplitude modulation. The value of $\sqrt{\mathrm{LC}}$ is

• $\frac{1}{2\mathrm{\pi } \times {10}^6}$

• $\frac{1}{2 \times {10}^6}$

• $\frac{1}{3\mathrm{\pi } \times {10}^6}$

• $\frac{1}{4\mathrm{\pi } \times {10}^6}$

An LED is constructed from a p-n junction based on a certain semi-conducting material whose energy gap is 1.9 eV. Then, the wavelength of the emitted light is

• 6.5 × 10^-7 m

• 2.9 × 10^-9 m

• 9.1 × 10^-5 m

• 1.6 × 10^-8 m

The given truth table is for

• NAND gate

• AND gate

• NOR gate

• OR gate

The input characteristics of a transistor in CE mode is the graph obtained by plotting

• I_B against I_C at constant V_CE

• I_B against V_BE at constant V_CE

• I_B against I_C at constant V_BE

• I_B against V_CE at constant V_BE

Constant DC voltage is required from a variable AC voltage. Which of the following is correct order of operation ?

• Regulator, filter, rectifier

• Rectifier, regulator, filter

• Rectifier, filter, regulator

• Filter, regulator, rectifier

In a transistor, the collector current varies by 0.49 mA and emitter current varies by 0.50 mA. Current gain β measured is

• 49

• 150

• 99

• 100

Identify the logic operation carried out by the following circuit

• AND

• NAND

• NOR

• OR

In the three parts of a transistor, 'Emitter' is of

• larger size and lightly doped

• moderate size and heavily doped

• thin size and heavily doped

• large size and moderately doped

The energy gap in case of which of the following is less than 3 eV ?

• Germanium

• Iron

• Copper

• Aluminium