Semiconductor Electronics: Materials, Devices and Simple Circuits

A transistor is operated in common emitter configuration V_C = 2V such that change n the base current from 100 µA to 300 µA produces a change in the collector current from 10 mA to 20 mA. The current gain is

• 75

• 100

• 25

• 25

The input signal given to a CE amplifier having a voltage gain of 150 is  The corresponding output signal will be

In the following figure, the diodes which are forward biased, are

Pure Si at 500 K has an equal number of the electron (n_e) and hole (n_h) concentrations of 1.5 x 10¹⁶ m^-3.Doping by indium increases n_h to 4.5 x 1022 m ^-3.The doped semiconductor is of 

• n- type with electron concentration n_e = 5 x 10²² m ^-3

• P- type with electron concentration n_e = 2.5 x 10¹⁰ m ^-3

• n- type with electron concentration n_e = 2.5 x 10²³ m ^-3

• n- type with electron concentration n_e = 2.5 x 10²³ m ^-3

A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in the figure. The current through the diode is

• 10 mA

• 15 mA

• 20 mA

• 20 mA

Which one of the following statement is false?

• Pure Si doped with trivalent impurities given a p- type semiconductor

• Majority carriers in a p- type semiconductor are holes

• Minority carriers in a p- type semiconductor are electron

• Minority carriers in a p- type semiconductor are electron

The device that can act as a complete electronic circuit is

• Junction diode

• Integrated circuit

• Junction transistor

• Junction transistor

A common emitter amplifier has a voltage gain of 50, an input impedance of 100 Ω and an output impedance of 200 Ω. The power gain the amplifier is 

• 500

• 1000

• 1250

• 1250

To get an output Y = 1 from the circuit shown below, the input must be

• A	B	C
  0	1	0

• A	B	C
  0	0	1

• A	B	C
  1	0	1

• A	B	C
  1	0	1

For transistor action

A) Base, emitter and collector regions should have similar size and doping concentrations.

B) The base region must be very thin and lightly doped.

C) The emitter-base junction is forward biased and base -collector junction is reverse biased

D) Both the emitter-base junction as well as the base-collector junction are forward biased.

• (D) and (A)

• (A) and (B)

• (B) and (C)

• (B) and (C)