Electronic Devices

A transistor is operated in common-emitter configuration at Vc = 2 V such that a change in the base current from 100 μA to 200 μA produces a change in the collector current from 5 mA to 10 mA. The current gain is

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

A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can be detect a signal of wavelength

A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly

P-type semiconductors are made by adding impurity element

The band gap in Germanium and silicon, in eV, are respectively

Depletion layer contains

Charge density for intrinsic semiconductor will be

The impurity atoms with which pure silicon may be doped to make it a p-type semiconductor are those of

Zenor breakdown will occur if

Energy bands in solids are a consequence of

In a transistor, the value of β is 100, then the value of α will be

For CE transistor amplifier, the audio signal voltage across the collector resistance of 2kΩ is 4V. If the current amplification factor of the transistor is 100 and the base resistance is 1kΩ, then the input signal voltage is

The Boolean expression P+ PQ, where P and Q are the inputs of the logic circuit, represents

When an input signal 1 is applied to a NOT gate, then its output is

In a common emitter transistor amplifier, the voltage gain is

The process of adding impurities to the pure semiconductor is called

In a n-p-n transistor about 10¹⁰ electrons enter the emitter in 2 μs, when it is connected to a battery. Then, Iᴇ = …….μA.

In a P-N junction

Zener breakdown in a semiconductor diode occurs when

The p-type semiconductor is

The current gain of a transistor in common base configuration is 0.96. Corresponding to the change in emitter current 10 mA, the change in base current would be

Function of a rectifier is

The liquid-crystal phase of a matter is called

The energy band gap is maximum in

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

For non-conductors, the energy gap is

In the middle of the depletion layer of a reverse-biased P-N junction, the

The conductivity in the intrinsic semiconductor does not depend on

If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be

In insulators (CB is Conduction Band and VB is Valence Band)

On adjusting the P-N junction diode in forward bias,

The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the

If the band gap between valence band and conduction band in a material is 5.0 eV, then the material is

The manifestation of band structure in solids is due to

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

Identify the wrong statement with reference to solar cell

In semiconductor at a room temperature

The output of OR gate is 1(one)

Zenor diode is used for

In common base circuit of a transistor, current amplification factor is 0.95. Calculate the emitter current, if base current is 0.2 mA.

In an NPN transistor the collector current is 24 mA. If 80% of the electrons reach collector, its base current in mA is

If α (current gain) of transistor is 0.98, then what is the value of β (current gain) of the transistor?

For the action of a common Base (CB) transistor, (E=emitter, B= base, C= collector) the required CB, EB junction bias conditions are

The minimum number of NAND gates used to construct an OR gate is

Copper has face centered cubic (fcc) lattice with interatomic spacing equal to 2.54 Å. The value of lattice constant for this lattice is

In a transistor the collector current is always less than the emitter current because

The term liquid crystal refers to a state that is intermediate between

When germanium is doped with phosphorus what type of semiconductor is produced?

In a vaccum triode the function of grid voltage is

In a ionised gas,the mobile charge carriers are

Which one of the following statements is not correct in case of a semiconductor?

In p- type semiconductor, the acceptor level lies

If the feedback voltage is increased in a negative feedback amplifier, then

When a p-n junction is reverse biased, then the current through the junction is mainly due to

What is the value of Ā+A in the Boolean algebra?

The depletion layer in the p-n junction region is caused by

For a cubic crystal structure which one of the following relations indicating the cell characteristics is correct?

The output of an AND gate is connected to both the inputs of a NOR gate, then this circuit will acts as a

The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be

In common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. The value of the base current amplification factor (β) will be

The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted. The resulting daughter is an

In intrinsic semiconductor at room temperature number of electrons and holes are

Sodium has body centred packing. Distance between two nearest atoms is 3.7 Å. The lattice parameter is

Minority carriers in a p-type semiconductor are

Which one of the following statement is FALSE about semiconductors?

Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point?

The device can act as a complete electronic circuit is

In depletion layer of unbiased P-N junction

For transistor action:
(1) Base, emitter and collector regions should have similar size and doping concentrations.
(2) The base region must be vary thin and lightly doped.
(3) The emitter-base junction is forward biased and base-collector junction is reverse based.
(4) Both the emitter-base junction as well as the base-collector junction are forward biased.

What is the voltage gain in a common-emitter amplifier, when input resistance is 4 Ω and load resistance is 24 Ω? Take β=0.6

In forward biasing of the p-n junction

To obtain a p-type semiconductor, germanium must be doped with

If a small amount of antimony is added to germanium crystal

If the highest modulating frequency of the wave is 5 kHz, the number of stations that can be accomodated in a 150 kHz bandwidth?

Pure Si at 500 K has equal number of electron [nₑ] 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

In communication with help of antenna if height is doubled then the range covered which was initially r would become

In the half wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be

C and Si both have same lattice structure, having 4 bonding electron in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because:

The number 0 (zero) is required for

The input resistance of a silicon transistor is 100 W. Base current is changed by 40 µA which results in a change in collector current by 2mA. This transistor is used as a common emitter amplifier with a load resistance of 4 KΩ. The voltage gain of the amplifier is:

In a n-type semiconductor, which of the following statement is true?

In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and current gain 25. If the above transistor is replaced with another one with transconductance 0.02 mho and current gain 20, the voltage gain will be

Carbon,silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate?

In an unbiased p-n junction, holes diffuse from the p-region to n-region because of

One way in which the operation of a n-p-n transistor differs from that of a p-n-p

The number of NAND gates required to form an AND gate is