Two sides of a semiconductor Germanium crystal A and B are doped with Arsenic and Indium, respectively. They are connected to a battery as shown in figure. The correct graph between current and voltage for the arrangement is :
In the network shown in figure, the potential of junction is
In the following circuit,the value of Y
The input signal given to a CE amplifier having a voltage gain of 150 is V i = 2 cos (15t + 10 0 ). The corresponding output signal is
For a common emitter amplifier, the audio frequency voltage across the collector resistance 2 kΩ is 2 V. If the current amplification factor of the transistor is 200, and the base resistance is 1.5 kΩ , the input signal voltage and base current are
The following configuration of gate is equivalent to
In a common – emitter configuration transistor amplifier, the load resistance of the output circuit is 1000 times the resistance of the input circuit, then the voltage gain is ( α = 0.98)
In n-p-n transistor, in CE configuration (a) The emitter is heavily doped than the collector (b) Emitter and collector can be interchanged (c) The base region is very thin but is heavily doped (d) The conventional current flows from base to emitter
The following figure shows a logic gate circuit with two inputs A and B and the output C. The voltage waveforms of A, B and C are as shown below. The logic gate is
To make a germanium crystal into a N type semi conductor the valency of the impurity atom that needs to be added is
In a common-base mode of transistor, the collector current is 5 488 mA for an emitter current of 5 .60 mA. The value of the base current amplification factor (p) will be
The output from a NAND gate is divided into two in parallel and fed to another NAND gate. The resulting gate is a
The combination of gates shown below yields
The valency of an impurity atom added to germanium crystal in order to convert it into a P-type semiconductor is
An N-type and P-type silicon can be obtained by doping pure silicon with
The circuit is equivalent to
In order to forward bias a PN junction, the negative terminal of battery is connected to
When a silicon PN junction is in forwad biased condition with series resistance , it has knee voltage of 0.6 V . Current flow in it is 5 mA , when PN junction is connected with 2.6 V battery , the value of series resistance is
Zener break down will occur if
The figureshows two NAND gates followed by a NOR gate. The system is equivalent to which of the following logic gate?
In a semiconductor,
The value of current gain α of a transistor is 0.98. The value of β will be
In a silicon transistor, the base current is changed by 20 μ A. This results in a change of 0.02 V in base to emitter voltage and a change of 2 mA in the collector current. The transistor is used as an amplifier with the load resistance of 5 k Ω . The change in output voltage across load is
When a p-n junction diode is reverse biased, then
Given below are four logic gate symbols. Those for OR, NOR and NAND gates are respectively
Assume that the silicon diode in the circuit requires a minimum current of 1 mA to be above the knee point (0.7 V) of I-V characteristics. Also assume that the voltage across the diode is independent of current above the knee point. If V B = 5V, then the maximum value of R so that the voltage is above the knee point is
A light emitting diode (LED) has a voltage drop of 2 V across it and passes a current of 10 mA. When it operates with a 6 V battery through a limiting resistor R, the value of .R is
In p-type semiconductor, conduction is due to
A junction diode has a resistance of 25 Ω when forward biased and 2500 Ω when reverse biased. then the current through the diode shown in the figure is
The correct curve between potential and distance near P-N junction is
A potential barrier V volts exists across a P-N junction. The thickness of the depletion region is ‘d’. An electron with velocity ‘v’ approaches P-N junction from N-side. The velocity of the electron crossing the junction is
A full wave p-n junction diode rectifier uses a load resistance of 1500 ohm. The internal resistance of each diode is 10 ohm. Find the efficiency of this full wave rectifier.
The equivalent resistance between A and B in ohm is V A > V B
Find the conductivity of intrinsic Silicon at 300 K. It is given that n i at 300 K in Silicon is 1 . 5 × 10 10 cm – 3 and the mobilities of electrons and holes in Silicon are 1300 cm 2 V – 1 s – 1 and 500 cm 2 / V-s respectively
Which of the following statement is not correct when a junction diode is in forward bias?
Two amplifiers are connected one after the other in series (cascaded). The first amplifier has a voltage gain of 10 and the second has a voltage gain of 20. If the input signal is 0.01 volt, calculate the output ac signal.
A zener diode in the circuit shown has a knee current of 5 mA and a maximum allowed power dissipation of 300 mW. What are the minimum and maximum load currents that can be drawn safely from the circuit, keeping the output voltage V 0 constant at 6 volts ?
A block of pure silicon at 300 K has a length 0 . t m and area of 1 ⋅ 0 × 10 − 4 m 2 if a battery of emf z y is connected across it, what is the electron current ? The mobility of electrons is 0 ⋅ 14 m 2 V − 1 s − 1 and their number density is 1 ⋅ 5 × 10 16 m − 3
Consider the junction diode as ideal. The value of current flowing through A B is
The barrier potential of a p-n junction depends on type of semiconductor material amount of doping temperature which one of the following is correct?
The given graph presents V-I characteristic for a semiconductor device. Which of the following statement is correct?
For a p -type semiconductor, which of the following statements is true?
The correct Boolean operation represented by the circuit diagram drawn is
The voltage gain of an amplifier without feedback is 100. Find voltage gain with 7% of negative feedback.
The input signal given to a CE amplifier having a voltage gain of 150 is V i = 2 cos 15 t + π 3 . The corresponding output signal will be
The output (X) of the logic circuit shown in figure will be
In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
In a p-n junction diode the thickness of depletion layer is 2 × 10 − 6 m and barrier potential is 0.3 V. The intensity of the electrical field at the junction is
The circuit diagram shown here corresponds to the logic gate,
From the circuit of the following Logic gates, the basic logic gate obtained is :
A transistor is connected in common emitter configuration. The collector – emitter voltage is 8 volt and a load resistance of 800 Ω is connected in the collector circuit. The voltage drop across the load resistance is 0.5 volt. If the current gain be 0.96, What is the base current?
In the given CE configuration and npn transistor with current gain β = 100, the output voltage of amplifier will be
Which logic gate is represented by the following combination of logic gates ?
In a semiconductor the separation between conduction band and valence band is of the order of
In case of a semiconductor, which of the following statements is wrong?
Select the correct statement.
Zener breakdown takes place if
The depletion layer in silicon diode is 1 µm wide and the knee potential is 0.6 V, then the electric field in the depletion layer will be
Consider the following statements A and B and identify the correct choice of the given answers. (A) A Zener diode is always connected in reverse bias. (B) The potential barrier of a PN – junction lies between 0.1 to 0.3 V approximately.
The resistance of a reverse biased P-N junction diode is about
The peak voltage in the output of a half-wave rectifier fed with a sinusoidal signal without filter is 10 V. The dc component of the output voltage is
A sinusoidal voltage of peak value 200 volt is connected to a diode and resistor R in the circuit shown so that half wave rectification occurs. If the forward resistance of the diode is negligible compared to R, the rms voltage (in volt) across R is approximately
When a silicon PN junction is in forward biased condition with series resistance , it has knee voltage of 0.6 V. Current flow in it is 5 mA, when PN junction is connected with 2.6V battery. The value of series resistance is
Ge and Si diodes conduct at 0.3 V and 0.7 V, respectively. In the following figure, if Ge diode connection are reversed, the valve of V 0 changes by
The transistors provide good power amplification when they are used in
For a transistor, the parameter β = 99. The value of the parameter α is
For a transistor, in a common emitter arrangement, the alternating current gain β is given by (All symblos have their usual meaning)
In a transistor in CE configuration, the ratio of power gain to voltage gain is
NPN transistor are preferred over PNP transistor because they have
An NPN -transistor circuit is arranged as shown in figure. It is
Identify the gate from the following.
Which logic gate is represented by following diagram?
In NPN transistor, 10 10 electrons enter in emitter region in 10 – 6 s. If 2% electrons are lost in base region, then collector current and current amplification factor β respectively are
The combination of NAND gates shown here under equivalent to – gate
In the given circuit each one of the diodes D 1 and D 2 has forward resistance of 40 ohm and infinite backward resistance. Each one of the ammeters A 1 , A 2 and A 3 has internal resistance 5 ohm. The readings of A 1 , A 2 and A 3 are respectively
When phosphorus and antimony are mixed in germanium, then
Which logic gate is represented by the combination of logic gates shown in figure?
In the common emitter configuration shown in figure on npn transistor with current gain β = 100 is used. The output voltage of the amplifier will be
Which of the following is not equal to 1 in Boolean algebra?
GaAs (with a band gap = 1.5 eV) as on LED can emit
The drift velocities of holes and electrons in a semiconductor are in the ratio 5 : 8. What will be the ratio of concentrations of electrons and holes if the ratio of electron current and hole current in a semi conductor is 7 : 5?
The truth table for the combination shown in figure is
In the given circuit, the voltage drop across 6 Ω resistor is
The truth table for the gate combination shown in figure is
The circuit diagram (see figure) shows a ‘logic combination’ with the states outputs X, Y and Z given for inputs P, Q R and S all at state 1 (i.e., high). When inputs P and R change to state 0 (i.e., low) with inputs Q and S still at 1, the condition of output X , Y and Z changes to
In the circuit shown in figure when the input voltage of the base resistance is 10V, V BE is zero and V CE is also zero. Find the values of I B , I C and β .
The following truth table belongs to which one of the following four gates?
The truth table given below is for
Which of the following gates will have an out put of 1?
How many NAND gates are used to form an AND gate
Which of these represents NAND gate?
The given truth table is of
If A and B are two inputs of AND gate, then AND gate has an output of 1 when the values of A and B are
The combination of gates shown below produces
Figure gives a system of logic gates. From the study of truth table it can be found that to produce a high output (1) at R, we must have
Statement I: If the temperature of a semiconductor is increased, then its resistance decreases. Statement II: The energy gap between conduction band and valence band in a semiconductor is very small.
Statement l: Zener diode works on a principle of breakdown voltage. Statement II: In Zener diode, current increases suddenly after breakdown voltage..
Statement I: A P-N photodiode is made from a semiconductor for which band gap E g – 2.8 eV. This photodiode will not detect the wavelength of 6000 nm. Statement II: A PN photodiode detect wavelength λ if energy of incident light, i.e., hc λ > E g . (Bandgap of semiconductor from which photodiode in made)
Statement I: De Morgan’s theorem A + B = A . B be explained by the following circuit. Statement II: In the following circuit, for output to be 1, inputs ABC are 101.
The circuit shown in following figure contains two diode D 1 and D 2 each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6 V the current through the I00 ohm resistance (in amperes) is
The output of a NAND gate is 0
The following configuration of gate is equivalent to
Which of the following logic gates is an universal gate?
In an unbiased p-n junction, if dope concentration in p-region is more than that in n-region, then
In a n-p-n transistor in common base configuration, keeping the base current unchanged if the collector-emitter voltage changes by 0.2 volt, it is observed that the collector current changes by 0.1 mA. Then output resistance of the transistor is
The electronic circuit shown in the figure represents a
The combination of gates shown in the figure is equivalent to
The dominant mechanisms for motion of charge carriers in forward and reverse biased silicon p-n junctions are,
n – p – n transistors are preferred to p – n – p transistors because
In an n-p-n transistor circuit the emitter current is 10 mA. If 10% of the emitted electrons are lost in the base, the base current is
The potential barrier of a P-N junction diode is 20 mV, when an electron having energy 400 meV travels from P to N, after crossing the junction the energy of the electron is
The equivalent resistance between A and B is
Which one of the following transistors is properly biased
The conductivity of pure semiconductor can be increased by
In the figure shown, the maximum and minimum currents through Zener diode are
In a transistor the current amplification factor α is 0.9. The transistor is connected in common emitter configuration, the change in collector current when base current changes by 4 mA is
The minimum number of NAND gates that are used to form AND gate is
The logic circuit shown in figure yields the following truth table. The gate X in the diagram is A B C 1 1 1 0 1 1 1 0 1 0 0 0
For a transistor, the current amplification factor α = 0 . 9 . This transistor is connected in common emitter configuration. When the base current changes by 0.4 mA, the change in collector current will be
In the depletion region of an unbiased p-n junction diode, There are
The dynamic forward resistance of an ideal p-n junction diode is
The base current of a transistor is 100 μ A and the collector current is 2 mA. What is the current gain for the common base configuration?
The real time variation of input signal A and B are as shown in the figure. Find the correct output signal if the inputs are fed into a NOR gate.
In the circuit shown, the transistor used has current gain β = 100 . What should be the base resistor Rb so that V CE = 5 V, V BE = O ?
Carbon, silicon and germanium have four valence elements each. At room temperature which one of the following statement[s) is most appropriate ?
The length of a germanium rod is 0.58 cm and its area of cross-section is 1 mm 2 . if for Germanium n i = 2 ⋅ 5 × 10 19 m − 3 , μ h = 0 ⋅ 19 m 2 / V − s μ e = 0 ⋅ 9 m 2 / V − s , then the resistance of the rod will be
Given density of carrier is 1⋅6×10 10 / cm 3 , carrier mobilities for electron and holes at 300 K are 1500 and 500 cm 2 volt-sec, electronic charge = 1 ⋅ 602 × 10 − 19 C Then the conductivity at 300 K of pure silicon is
The ratio of electron and hole currents in a semiconductor is 5/4 and the ratio of drift velocities of electron and holes is 7/4, then the ratio of concentrations of electrons and holes will be
What will be the conductivity of pure silicon crystal at 300 K temperature if electron cotter pair at this temperature is 1 ⋅ 072 × 10 10 / cm 3 and μ n = 1350 cm 2 / V − s and μ p = 480 cm 2 / V − s ?
Given density of carriers is 1 ⋅ 6 × 10 10 / cm 3 carrier mobilities for electrons and holes at 300 K ale 1500 and 500 cm 2 / volt − sec electronic charge = 1 ⋅ 602 × 10 − 19 C Then the resistivity at 300 K is
What is the voltage gain in a common emitter amplifier, where input resistance is 3 Ω and load resistance 24 Ω ? (Tale β = 0.6
If all diodes are ideal then current through the resistance R is
The conductivity of a semiconductor increases with temperature because
A silicon specimen is made into a p – type semiconductor by doping on an average, one indium atom per 5 x 10 7 silicon atoms. If the number density of atoms in the silicon specimen is 5 x 10 28 atoms/ m 3 , then the number of acceptor atoms in silicon per cubic centimeter will be
In the combination of the following gates the output Y can be written in terms of inputs A and B as
In the circuit shown in the figure, the input voltage V i is 20 V B E = 0 and V C E = 0 . The values of I B , I C and β are given by
To convert an intrinsic semiconductor to an extrinsic one with electrons as majority carriers, the intrinsic semiconducting material must be doped with
For an ideal diode, the dynamic forward resistance should be
To get output 1 for the following circuit, the correct choice for the input is
A npn transistor is connected in common emitter configuration in a given amplifier. A load resistance of 800 Ω is connected in the collector circuit and the voltage drop across it is 0 . 8 V . If the current amplification factor is 0.96 and the input resistance of the circuit is 192 Ω , the voltage gain and the power gain of the amplifier will respectively be
Which logic gate is represented by the following combination of logic gate ?
The voltage across capacitor C is
The electrical conductivity of a semiconductor increases when electro magnetic radiation of wavelength shorter than 2480 nm is incident on it. The band gap (in eV) for the semiconductor is
The waveform of input A and B and the output C is given below. The logic circuit gate is
In the given figure, a diode D is connected to an external resistance R = 100 Ω and an e.m.f. of 3.5 V. If the barrier potential developed across the diode is 0.5 V, the current in the circuit will be
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 rnho and current gain 20, the voltage gain will be
In a n-type semiconductor, which of the following statement is true.
Which logic gate is represented by the following combination of logic gates?
The concentration of impurities in a transistor is
An n-p-n transistor conducts when :
If in a p-n junction, a square input signal of 10 V is applied, as shown, then the output across R L will be
For CE transistor amplifier, the audio signal voltage across the collector resistance of 2 k Ω is 4V. If the current amplification factor of the transistor is 100 and the base resistance is 1 K Ω , then the input signal voltage is
The given circuit has two ideal diodes connected as shown in the figure. The current flowing through the resistance R 1 will be
What is the output Y in the following circuit, when all the three inputs A, B, C are first 0 and then 1 ?
One way in which the operation of a n-p-n transistor differs from that of a p-n-p
The reverse bias in a junction diode is changed from 5 volt to 15 volt then the value of current changes from 38 μ A to 88 μ A . The resistance of junction diode will be
The current gain of transistor in common emitter circuit is 40. The ratio of emitter current to base current is
Ge and Si diodes conduct at 0.3 V and 0.7 V respectively, if Ge and Si diode are reverse biased in turn, the value of V 0 changes by
In a common emitter transistor amplifier the audio signal voltage across the collector is 3 V. The resistance of collector is 3 k Ω . If current gain is 100 and the base resistance is 2 k Ω , the voltage and power gain of the amplifier is
The given electrical network is equivalent to
Which one of the following represents forward bias diode?
An intrinsic semiconductor is converted into n-type extrinsic semiconductor by doping it with
The increase in the width of the depletion region in a p-n junction diode is due to :
For transistor action, which of the following statements is correct?
For the logic circuit shown, the truth table is :
The solids which have the negative temperature coefficient of resistance are:
Out of the following which one is a forward biased diode?
n-p-n transistor is connected in common emitter configuration (see figure)in which collector voltage drop across load resistance (800 Ω ) connected to the collector circuit is 0.8 V. The collector current is
Which of the following gate is called universal gate ?
A transistor is connected in common emitter configuration. The collector supply is 8V and the voltage drop across a resistor of 800 Ω in the collector circuit is 0.5 V. If the current gain factor α is 0.96, the base current will be
When a p n junction is forward biased
A Zener diode is connected to a battery and load as shown below: The currents I , I Z a n d I L are respectively
A potential barrier V volts exists across a P-N junction. The thickness of the deplection region is ‘d’. An electron with velocity ‘V’ approaches P-N junction from N-side. The velocity of the electro a crossing the junction is
In the circuit below A and B represent two inputs and C represents the output the circuit represents
The gate represented by the block diagram is :
In a p-n junction diode, change in temperature due to heating
An LED is constructed from a p-n junction diode using Ga As P. The energy gap is 1.9 eV. The wavelength of the light emitted will be equal to
A common emitter amplifier circuit is shown in the figure below. For the transistor used in the circuit the current amplification factor, β d c = 100 . Other parameters are mentioned in the figure. We find that :
Which logic gate is represented by the following combination?
For a transistor I c I E = 0 . 96 , Then current gain for common emitter is
If dope concentration of both P and N region is increased, thickness of depletion layer
The combination of the gates shown in figure, produces
In an n–p–n transistor, current gain for common emitter configuration is 80. If the emitter current be 8.1 mA, Then the base current is
The configuration of gate shown in figure is equivalent to
The current amplification of the common base p–n–p transistor is 0.96. What is the current gain for the common emitter amplifier?
In an n-p-n transistor, 10 8 electrons enter the emitter in 10 – 8 sec . If 1% electrons are lost in the base, the fraction of current that enters the collector and current amplification factor are respectively
In the given circuit, the voltage drop across 6 Ω resistance is—
A sinusoidal voltage of rms value of 200 volt is connected to the diode and a capacitor C in the circuit as shown, so that half wave rectification occurs. The final potential difference in volt across C is
Consider the combination of two NOR gates shown in figure.The output Y for A=B=C=1 is,
The nature of binding for a crystal with alternate and evenly spaced positive and negative ions is
The temperature coefficient of resistance of a semiconductor
The temperature coefficient of resistance of a conductor is
Metallic solids are always opaque because
Silicon is a semiconductor. If a small amount of As is added to it, then its electrical conductivity
Electrical conductivity of a semiconductor
Three semiconductors are arranged in the increasing order of their energy gap as follows. The correct arrangement is
A pure semiconductor has equal electron and hole concentration of 10 16 m – 3 . Doping by Indium increases n h to 4 . 5 × 10 22 m – 3 . What is n e in the doped semiconductor?
Semiconductor is damaged by the strong current due to
Which of the following has negative temperature coefficient of resistance?
In semiconductors, at room temperature
Regarding a semiconductor which one of the following statements is wrong?
Choose the correct statement.
Resistance of semiconductor at 0 K is
When an impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor
If n e and n h are the number of electrons and holes in a semiconductor heavily doped with phosphorus, then
The electrical resistance of which of the following decreases with rise in temperature?
Iron and silicon wires are heated from 30°C to 50°C. The correct statement is that
The valence band and conduction band of a solid overlap at low temperature , the solid may be
An intrinsic semiconductor at absolute zero of temperature behaves as
When the temperature of silicon sample is increased from 27°C to 100°C, the conductivity of silicon will
In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
The forbidden energy band gap in conductors, semiconductors and insulators are EG 1 , EG 2 and EG 3 respectively. The relation among them is
The forbidden gap in the energy bands of germanium at room temperature is about
In a good conductor, the energy gap between the conduction band and the valence band is
In a P-type semiconductor, Germanium is doped with
To obtain a P-type germanium semiconductor, it must be doped with
A P-type semiconductor is formed when A . As impurity is mixed in Si B. Al impurity is mixed in Si C. B impurity is mixed in Ge D. P impurity is mixed in Ge
In a P-type semiconductor,
A semiconductor doped with a donor impurity is
Electronic configuration of germanium is 2, 8, 18 and 4. To make it extrinsic semiconductor small quantity of antimony is added.
An N-type semiconductor is
When Ge crystals are doped with phosphorus atom, then it becomes
Let n P and n e be the number of holes and conduction electrons respectively in a semiconductor. Then
For germanium crystal,the forbidden energy gap in joules is
n e and v d are the number of electrons and drift velocity in a semiconductor . When temperature is increased
The energy gap of silicon is 1.14 eV. The maximum wavelength at which silicon will begin absorbing energy is
A diode having potential difference 0.5 Volt across its junction which does not depend on current is connected in series with resistance of 20 Ω across source. If 0.1A current passes through the resistor, then what is the voltage of the source
An n-p-n transistor conducts when :
A transistor amplifier with suitable feedback from output side to input side can produce self-sustained oscillations and the circuit becomes an electronic oscillator. The required feedback must be
A pure Ge crystal has 3.0× 10 28 atoms / m 3 . It is doped by 1 part per 10 million concentration of trivalent Ga. The number density of electrons is (Given that n i =1.5× 10 16 / m 3
Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by ( E g ) C , ( E g ) si and ( E g ) Ge , respectively. Which one of the following relationship is true in their case?
If N P and N e be the numbers of holes and conduction electrons in an extrinsic semiconductor, then
In intrinsic semiconductor at room temperature, number of electrons and holes are
When the electrical conductivity of a semiconductor is due to the breaking of its covalent bonds, then the semiconductor is said to be
In extrinsic semiconductors
On increasing the reverse bias to a large value in a PN junction diode, current
In the forward bias arrangement of a PN-junction diode
Barrier potential of a p-n junction diode does not depend on
The electrical circuit used to get smooth dc output from a rectifier circuit is called
In a PN-junction diode,
In forward bias, the width of potential barrier in a P – N junction diode
PN-junction diode works as an open switch if connected
Avalanche breakdown is due to
In a P-N junction diode if P region is heavily doped than n region , then the depletion layer is
Zener breakdown in a semiconductor diode occurs when
Function of rectifier is
A potential barrier of 0.50 V exists across a P-N junction. If the depletion region is 5 . 0 x 10 – 7 m wide, the intensity of the electric field in this region is
If the two ends P and N of a P-N diode junction are joined by a wire
If P-N junction diode is in forward biased, then
In a PN – junction,
In the middle of the depletion layer of a reverse-biased PN – junction, the
Which impurity is doped in Si to form N- type semi conductor ?
In a given circuit as shown the two inputs waveform A and B applied simultaneously. The resultant wave form Y is
The maximum efficiency of full wave rectifier is
In P-N junction, avalanche current flows in circuit when
The depletion layer in the P-N junction region is caused by
The reason of current flow in P-N junction in forward bias is
Zener diode is used as
In P-N junction, the barrier potential offers resistance to
In a forward biased PN-junction diode, the potential barrier in the depletion region is of the form
Consider the following statements A and B and identify the correct choice of the given answers. A. The width of the depletion layer in a P-N junction diode increases in forward bias. B. In an intrinsic semiconductor the fermi energy level is exactly in the middle of the forbidden gap.
In the case of forward biasing of PN-junction, which one of the following figures correctly depicts the direction of flow of carriers?
Which one is in forward bias?
The forward biased diode is
Which of the following is reverse biased?
Which of the following is reverse biased diode
Of the diodes shown in the following diagrams, which one is reverse biased?
The correct symbol for Zener diode is
Symbolic representation of photodiode is
Which is the correct diagram of a half-wave rectifier?
the current through an ideal PN-junction shown in the following circuit diagram will be
In a full wave rectifier, input ac current has a frequency ν . The output frequency of current is
The diode used in the circuit shown in the figure has a constant voltage drop of 0.5 V at all currents and a maximum power rating of 100 milliwatts. What should be the value of the resistance R, connected in series with the diode for obtaining maximum current?
The phase difference between input and output voltages of a CE circuit is
In an NPN transistor circuit, the collector current is 10rnA.If 90% of the electrons emitted reach the collector, the emitter current ( i E ) and base current ( i B ) are given by
In a common emitter transistor, the current gain is 80. What is the change in collector, when the change in base current is 250 μA
A common emitter amplifier is designed with NP transistor (a =0.99). The input impedance is 1k Ω and load is 10 k Ω . The voltage gain will be
For a transistor, the current amplification factor is 0.8. The transistor is connected in common emitter configuration . The change in the collector current when the base current changes by 6 rnA is
Which of the following is used to produce radio waves of constant amplitude?
In the study of transistor as an amplifier, if α = I c / I e and β = I c / I e , where l c , l b and l e are the collector, base and emitter currents, then
In the following common emitter configuration, an n-p-n transistor with current gain β = 100 is used . The output voltage of the amplifier will be
In the following common emitter circuit, if β =100, V CE = 7 V , V BE = negligible , R C = 2 kΩ , then I B = ?
Which gate is represented by the figure given below?
The depletion region in the P-N junction region is caused by
The diagram shows a logic network If the inputs L, M and N are all at logic 1, what are the logic states of P, Q and R
A common emitter amplifier is designed with npn transistor α = 0 .99 . The input impedance is 1 KΩ and load is 10 KΩ . The voltage gain will be
in the given circuit as shown, the two input wave forms A and B are applied simultaneously. The resultant waveform Y is
The cause of potential barrier in the p n junction is
What is the voltage gain in a common base amplifier where input resistance is 3 ohms and load resistance is 24 ohms ? (Take α = 0.6)
In PN – junction diode the reverse saturation current is 10-5 amp at 27º C . The forward current for a voltage of 0.2 volt is
In the common emitter circuit shown in figure, if V B E = 2 v o l t , V C E = 5 v , β = 100 , Then base current I B i s
For the combination of gates shown in figure, the correct truth table is
The combination of gates shown in figure is equivalent to
In a transistor circuit, the base current changes from 30 μ A t o 90 μ A . If the current gain of the transistor is 30, the change in emitter current is
The logic circuit shown in figure is equivalent to
In the diagram, the input is across the terminals A and C; output is across the terminals B and D. Then the out put is
Current gain in CB configuration of a transistor is 0.95. What is the power gain in CE configuration of this transistor if the input resistance is 3 Ω and load resistance is 24 Ω ?
In a transistor amplifier β=62, R L = 5000 Ω and input resistance of the transistor is 500 Ω . Its power amplification will be
The given figure shows the wave forms of two input signals A and B and that for the output Y of a logic circuit. The logic circuit is
With reference to figure, which of the following is possible?
In a transistor, if current amplification factor for common base configuration is 0.95, then current amplification factor for common emitter configuration will be
The waveform of input A and B and the output C is given below. The logic circuit gate is
Which of the following gates corresponds to the truth table given below?
The waveform of input A and B and the output C is given below. The logic circuit gate is
For the given combination of gates, if the logic states of inputs A,B,C are as follows: A=B=C=0 and A=B=1, C=0, then the logic states of output d are respectively
The logic behind ‘NOR’ gate is that it gives
The combination of the gates shown in the figure below produces
The diagram of a logic circuit is given below. The output F of the circuit is represented by
In semiconductor the concentrations of electrons and holes are 8 x 10 18 / m 3 and 5 x 10 18 / m 3 , respectively. If the mobilities of electrons and holes are 2.3 m 2 /V-s and 0.01 m 2 /V-s, respectively, then resistivity of semiconductor is
Identify the logic gate G in the combination of gates shown in figure. The truth table is shown here.
The current amplification of the common base NPN transistor is 0.96. What is the current gain if it is used as common emitter amplifier?
A transistor is used in a common-emitter mode in an amplifier circuit. When a signal of 20 mV is added to the base-emitter voltage, the base current changes by 20 µA and the collector current changes by 2 mA. The load resistor in 5 k Ω . What is the value of β ?
Figure shows a piece of semiconductor (pure one) S in series with a variable resistor R and a source of constant voltage V. S is heated and the current is kept constant by adjustment of R. Which of the following factors will decrease during this process? The drift velocity of the conduction electrons in S. The DC resistance of S The number of conduction electrons in S.
In the circuit shown, the base current is 30 µA. The value of R 1 is (Neglect V BE )
In a common emitter amplifier, using output resistance of 5000 ohm and input resistance of 2000 ohm, if the peak value of input signal voltage is 10 mV and β = 50, then the peak value of output voltage is
The diagram shows a logic network. If the inputs L, M and N are all at logic 1, what are the logic states of P, Q and R?
What is the output in the given figure?
A digital system comprises a AND gate with a NOT gate on each of its inputs as shown in figure. To which of the following single gates is this system equivalent?
A combination of logic gates has the truth table shown below: Which combination has this table?
The diagram shows a logic network. Which single gate is equivalent to the network?
In PN-junction diode the reverse saturation current is 10 – 5 A at 27°C. The forward current for a voltage of 0.2 volt is
Figure shows a circuit designed to control a lamp. For what positions of the switches S 1 and S 2 will the lamp be lit?
Figure shows a combination of logicgates. To what single gate is this combination equivalent?
A potential difference of 2V is applied between the opposite faces of a Ge crystal plate of area 1 c m 2 and thickness 0.5 mm. If the concentration of electrons in Ge is 2 × 10 19 / m 3 and mobilities of electrons and holes are 0.36 m 2 volt – sec and 0 . 14 m 2 volt – sec , respectively, then the current flowing through the plate will be
The contribution in the total current flowing through a semiconductor due to electrons and holes are ¾ and ¼ , respectively. If the drift velocity of electrons is 5/2 times that of holes at this temperature, then the ratio of concentration of electrons and holes is
The intrinsic semiconductor becomes an insulator at
For a common base configuration of PNP transistor, l C l E = 0.96, then maximum current gain in common emitter configuration will be
Which gate is represented by the following truth table?
Following diagram performs the logic function of
The output of OR gate is 1
In a p-n junction photocell, the value of the photo electromotive force produced by monochromatic light is proportional to
A npn transistor conducts when the base
Choose the false statement from the following:
Zener diode is used for
Application of a forward bias to a p-n junction
The following figure shows a logic gate circuit with two inputs ,A and B and the output C. The voltage wave forms of A, B and C are as shown below The logic circuit gate is
A transistor is operated in common emitter configuration at constant collector voltage V c = 1.5 V such that a change in the base current from 100 µA to 150 µA produces a change in the collector current from 5 mA to 10 mA. The currentgain ( β )is
In the following circuit, the output Y for all possible inputs A and B is expressed by the truth table
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 of the amplifier is
In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is a/an
The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be
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
The circuit is equivalent to
A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength
The current gain for a transistor working as a common-base amplifier is 0.96. If the emitter current is 7.2 mA, the base current will be
A 0 K temperature, a p-type semiconductor
When added an impurity into the silicon, which one of the following produces n-type of semiconductors?
Statement I: Silicon is preferred over germanium for making semiconductor devices. Statement II: The energy gap for germanium is more than the energy gap of silicon.
Statement I: NAND or NOR gates are called digital building blocks. Statement II: The repeated use of NAND (or NOR) gates can produce ail the basic or cornplicated gates.
Statement I: In transistor, common emitter mode as an amplifier is preferred over common base mode. Statement II: In common emitter mode, the input signal is connected in series with the voltage applied to the base emitter junction.
Statement I: Base in a transistor is made very thin as compared to collector and emitter regions. Statement II: Due to thin base, power gain and voltage gain is obtained by a transistor.
Statement I: At 0 K, Germanium is a superconductor. Statement II: At 0 K. Germanium offers zero resistance.
Statement I: The resistivity of a semiconductor increases with temperature. Statement II: The atoms of a semiconductor vibrate with larger amplitude at higher temperatures, thereby increasing its resistivity.
Statement I: In a transistor, the base is made thin. Statement II: A thin base makes the transistor stable.
Statement I: When PN-junction is forward biased, then motion of charge carriers at junction is due to diffusion. In reverse biasing, the cause of motion of charge is drifting. Statement II: In the following circuit, emitter is reverse biased and collector is forward biased
Statement I: A transistor amplifier in common emitter configuration has a low input impedance. Statement II: The base to emitter region is forward biased.
Statement I: Diode lasers are used as optical sources in optical communication. Statement II: Diode lasers consume less energy.
Statement I: We can measure the potential barrier of a PN junction by putting a sensitive voltmeter across its terminals. Statement II: The current through the PN-junction is not same in forward and reversed bias.
Statement I: The value of current through p-n junction in the given figure will be 10 mA. Statement II: In the above figure, p-side is at higher potential than n-side.
Statement I: The logic gate NOT can be built using diode. Statement II: The output voltage and the input voltage of the diode have 180 0 phase difference.
Statement I: A p-n junction with reverse bias can be used as a photo-diode to rneasure light intensity. Statement II: In a reverse bias condition, the current is small but it is more sensitive to change in incident light intensity.
Statement I: In a CE transistor amplifier, the output voltage is always out of phase with the input voltage. Statement II: The emitter base junction of CE amplifier is reverse biased and the base collector junction is forward biased.
Energy bands in solids are a consequence of
When NPN transistor is used as an amplifier
When forward bias is applied to a P-N junction, then what happens to the potential barrier V B , and the width of charge depleted region x?
If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be
To obtain P-type Si semiconductor, we need to dope pure Si with
The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature
In a common base amplifier, the phase difference between the input signal voltage and the output voltage is
In the circuit given below, V(t) is the sinusoidal voltage source. Voltage drop V AB (t) across the resistance R
Given below are symbols for some gates. The OR gate and the AND gate, respectively are
Consider an n-p-n transistor amplifier in common-emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current?
An amplifier has a voltage gain, A v = 1000. The voltage gain in dB is
The circuit given below represents which of the logic operations?
The minimum potential difference between the base and emitter required to switch a silicon transistor ‘ON’ is approximately
The input resistance of a common emitter transistor amplifier, if the output resistance is 500 k Ω , the current gain α = 0.98 and power gain is 6 . 0625 x 10 6 , is
The potential barrier developed in the diode shown in figure below is 0.5 V. The current through the diode is
The combination of gates represents
In a common emitter transistor, β = 100 and transconductance g m = ∆ I C ∆ V B E is 0.2 ( ohm ) − 1 . Then its input resistance is
The width of depletion layer is a p-n junction decreases due to
The combination of gates shown in figure, represents
The logic gate represented by the circuit diagram is
When a common emitter transistor is acting as an amplifier,
The combination of gates shown in figure represents
Which of the following options represents forward biased p-n junction?
A transistor is used as an amplifier. A resistance of 0 .5 k Ω is connected as load resistance in the collector circuit. When base current changes by 80 μ A , the potential drop in the load resistance changes by 4 volt. The current amplification factor of transistor is
In a silicon crystal, the valence and conduction band are separated by a forbidden band of energy
Which one of the following is the truth table of the given logic circuit?
Pure Si at 300 K has equal electron ( n e ) and hole ( n h ) concentration of 1 . 5 × 10 16 m – 3 . It is doped with 4 . 5 × 10 22 m – 3 Indium. Calculate n e in the doped Silicon
The electrical conductivity of a semi conductor increases when electro magnetic radiation of wavelength shorter than 2480 nm is incident on it. The forbidden band gap for the semi conductor is
The width of forbidden gap in Silicon crystal is 1.1 eV. When the crystal is converted into p-type semiconductor, the distance of fermi level from conduction band is
A semiconductor P-N junction is to be forward biased with a battery of e.m.f. 1.5 volt. If a potential difference of 0.5 V appears on the junction which does not depend on current. Then to use the junction at 5 mA current, the resistance required to be connected in its series will be
A diode made of Silicon has a barrier potential of 0.7 V and a current of 20 mA passes through the diode, when a battery of 4 V and a resistance R are in series to it. The wattage of the resistor is
Which of the following statement in not correct in case of Photo diode ?
For the transistor given below the value of β is 100 and collector current is 2.5 mA, then value of V CE will be
For a single transistor amplifier, the collector load is R L = 2 kΩ and input resistance R i = 1 kΩ . If the current gain is 50, then the voltage gain of the amplifier is
A transistor connected in common emitter configuration has input resistance R in = 2 kΩ and load resistance of 5 kΩ . If β = 60 and an input signal 12 mV is applied. The power gain is
In the following common emitter circuit if β = 100 , V CE = 7 V , V BE is negligible , R c = 2 kΩ , then I B =
In a n-p-n transistor 10 10 electrons enter the emitter in 10 -6 s. 4% of the electrons are lost in base. The current transfer ratio will be
To get an output y = 1 from circuit of Figure, the input A, B and C respectively must be
The output Y of the logic circuit shown in figure is best represented as
In the circuit, transistor has a current gain β = 100 , the base resistor R b is (neglect V BE ) so that V CE = 5 V
In an n-p-n transistor
Avalanche breakdown in a semiconductor diode occurs when
A Zener diode voltage regulator operated in the range 120 -180 V produces a constant supply of 110 V and 250 mA to the load. If the maximum current is to be equally shared between the load and the Zener diode, then the values of series resistance (R S ) and load resistances (R L ) in ohms are
The resistance of the diode in the forward biased condition is 10 ohm and infinity in the reverse biased condition. The current in the given circuit is
To get an output 1 from the circuit shown in the figure, The input must be :
A full- wave rectifier is used to convert ‘n’ Hz A.C into D.C, then the number of pulses per second present in rectified voltage is
Truth table for system of four NAND gates as shown in figure
The combination of gates shown in figure represents a
The diode shown in the figure is an ideal diode, then reading of the ideal ammeter A is
What accounts for the flow of charge carriers in forward and reverse biasing of silicon p-n diode?
Expression for XOR gate is
When a junction diode is reverse biased, what causes current across the junction?
Which of the following gates can have only one input?
A semiconductor is known to have an electron concentration of 8 × 10 13 per cm³ and a hole concentration of 5 × 10 12 per cm³. The semiconductor is
If N p and N e be the numbers of holes and conduction electrons in an extrinsic semiconductor, then :
D 1 and D 2 conduct at 0.2 V and 0.4 V respectively. The current flowing through resistor is
When the electrical conductivity of a semiconductor is due to the breaking of its covalent bonds, then the semiconductor is said to be
The output current versus time curve of a rectifier is shown in the figure. The average value of output current in this case is :
Let the input to a full-wave rectifier be e = 50 sin (314t) volt and its diode and load resistances are 100 Ω and 1 Ω, respectively. Consider the following statements. (I) its pulse frequency of output voltage is 100 (II) its input power is 1136 mW (III) its output power is 838 mW (IV) its efficiency is 81.2% Which of the options is correct based on the above information?
In a p-n junction diode a square input signal of 10 V is applied as shown, output signal across R will vary as
Find the current across the P- N junction diode shown the figure. (Assume the diode junction to be ideal)
What is the voltage gain of a common emitter amplifier where input resistance is 3 Ω and load resistance is 24 Ω ? (given, β = 6 )
In the following common emitter configuration, an n-p-n transistor with current gain, β = 100 is used. The output voltage of the amplifier will be
