Electronic Devices — practice questions

71 curated practice questions from Electronic Devices (Physics JEE Main, NTA Exams) — 70 easy, 1 medium. Every question includes the final answer free; step-by-step worked solutions with a free account.

The emitter of transistor is doped the heaviest because it: (I) acts as a supplier of charges carriers. (II) dissipates…
In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be
A silicon specimen is made into a p-type semiconductor by doping, on an average, one Indium atom per 5×10 7 silicon…
Current in the circuit shown here is (assume diodes are ideal):
Two ideal p-n junction diodes are connected in an electrical circuit with resistances to a battery of 12V as shown in…
When the forward bias voltage of a diode is changed from 0.6 V to 0.7 V the current changes from 5 mA to 15 mA. Then…
An n-type and p-type silicon semiconductor can be obtained by doping pure silicon with :
A n-p-n transistor power amplifier in CE configuration gives
Which of these are correct ? I. In forward biasing, holes from p-side crosses junction and reach n-side. II. In forward…
In a common base amplifier, the phase difference between the input signal voltage and output voltage is
The following circuit represents :
By increasing the temperature, the specific resistance of a conductor and a semiconductor
In the reverse-biased p-n junction, the current is of the order of :
The forbidden energy gap in the energy bands of germanium at room temperature is about :
To get an output 1 from the circuit shown in the figure, the input must be
The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to…
In the given circuit, the output Y becomes zero for the inputs :
A transistor having a β equal to 80 has a change in base current of 250 µ amp, then the change in collector current is :
In the given circuit, if the forward voltage drop for the diode is 0.5 V, the current is
In common emitter amplifier, the current gain is 62. The collector resistance and input resistance are 5 kΩ and 500Ω…
Acceptor atoms introduced into a pure semiconductor at room temperature :
Which of the following is NOT true when a reverse bias is applied to a p-n junction ?
In an n-p-n circuit transistor, the collector current is 10 mA. If 80% electrons emitted reach the collector, then :
An n-p-n transistor circuit is arranged as shown in figure. It is :
In the circuit below, A and B represent two inputs and C represents the output. The circuit represents
When the emitter current of a transistor is changed by 1 mA, its collector current changes by 0.990 mA. The common base…
Carbon is more resistive than germanium and silicon. Then, order of energy gap is :
A transistor is used in common-emitter mode as an amplifer. Then :
The current gain of the common base n-p-n transistor is 0.96. What is the curent gain if it is used as common-emitter…
The correct relationship between the two current gains α and β in a transistor is :
The circuit in the below figure represents which of the logic operations?
A transistor is operated in common emitter configuration at constant collector voltage V c = 1.5 V, such that a change…
If I is total current through an intrinsic semiconductor and I e is electron current and I h is hole current, then :
The electrical circuit used to get smooth DC output from a rectifier circuit is called :
The minimum potential difference between the base and emitter required to switch a silicon transistor ‘ON’ is…
Output Y is given by :
The peak voltage in the output of a half-wave diode rectifier fed with a sinusoidal signal without filter is 10 V. The…
For a transistor, in a common-emitter arrangement, the AC current gain β is given by :
A piece of Copper and another of Germanium are cooled from room temperature to 77 K, the resistance of
If n e is number density of electrons in conduction band and n h is number density of holes in valence band, then for…
A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength:
An n-type and p-type silicon can be obtained by doping pure silicon with :
In forward bias, forward current obtained from the p-n junction diode is :
In a negative logic, voltage representation the following waveform corresponds to :
When germanium is doped with phosphorus, the doped material has :
At elevated temperature, few of covalent bonds of Si or Ge are broken and a vacancy in the bond is created. Effective…
The depletion layer in the p-n junction region is caused by:
In an n-p-n transistor circuit, the collector current is 9 mA. If 90% of the electrons emitted reach the collector…
The following configuration of gate is equivalent to :
The truth table given below is for (A and B are the inputs, Y is the output) A B Y 0 0 1 0 1 1 1 0 1 1 1 0
Symbol of a p-n junction diode is an arrow, its direction indicates :
In a p-type semiconductor, the majority and minority charge carriers are respectively,
Find V AB for the following circuit (consider ideal diode):
A transistor connected in common emitter configuration has input resistance R CE = 2Ω and load resistance of 5 kΩ. If β…
Consider the following statements (A) and (B) and identify the correct answer. A zener diode is connected in reverse…
The probability of electrons to be found in the conduction band of an intrinsic semicondutor at a finite temperature:
The gap between the valence and conduction bands of a certain semiconductor is 0.85 eV. When this semiconductor is used…
For the given circuit of p-n junction diode, which of the following statement is correct ?
The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An…
In equilibrium condition, the rate of generation of electron-hole pairs:
Which of the given statements are correct regarding unbiased p-n junction ? I. Drift and diffusion currents occur p to…
The correct option for getting X = 1 from the given circuit is
When a transistor is biased as follows: Then, it is said to be in :
The current gain for a transistor working as common base amplifier is 0.96. If the emitter current is 7.2 mA, then the…
The current gain α of a transistor in common base mode is 0.995. It gain β in the common emitter mode is
The Sinusoidal output current versus time curve of a rectifier is shown in figure. The average value of the output…
The forward characteristic of p-n junction is shown in the figure. What is the dynamical resistance of p-n junction at…
Identify the gate and match A, B, Y in bracket to check.
A zener diode is connected to a battery and a load as shown below: The currents I, I Z and I L are respectively
Due to diffusion of electrons from n to p-side, I. electron-hole combination across p-n junction occurs. II. an ionised…
A sinusoidal voltage of peak value 200 V is connected to a diode and resistor R in the cirucuit shown so that half-wave…

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