Semiconductor Electronics: Materials,Devices And Simple Circuits - Class 12 Engineering Physics - Extra Questions
What is the energy band gap of: (i) silicon and (ii) germanium
What is a hole? Which type of doping creats a hole?
Identify the logic gate whose truth table is given below and draw its symbol:
A
B
Y
0
0
1
0
1
1
1
0
1
1
1
0
Draw the truth table of a NOR gate.
Which gates are called universal gates?
The use of zener diode is as ________.
What is a NAND gate? Give its logic symbol.
Write one main use of Zener diode.
What is Zener diode? How is it used as a voltage regulator?
Construct a AND gate using only NOR gates only
A coil a current of 1.0 ampere and a power of 100. Find the Resistance.
Which device is used as a voltage regulator ?
Distinguish between 'paramagnetic' and 'ferromagnetic' substances.
Name the logic gate which generates high output when at least one input is high.
The number of silicon atoms per m3 is 5×1028. This is doped simultaneously with 5×1022 atoms per m3 of arsenic and 5×1020 per m3 atoms of indium. Calculate the number of electrons and holes. Given that ni=1.5×1016/m3. Is the material n-type or p-type?
Write the truth table for a NAND gate connected as given in Figure.
You are given two circuits as shown in Fig., which consist of NAND gates. Identify the logic operation carried out by the two circuits.
What happens when a forward bias is applied to a p-n junction?
Identify the gates P and Q shown in figure. Write the truth table for the combination of the gates shown. Name of equivalent gate representing this circuit and write its logic symbol
(a) Explain briefly the principle on which a transistor-amplifier works as an oscillator. Draw the necessary circuit diagram and explain its working. (b) Identify the equivalent gate for the following circuit and write its truth table.
(a) Describe briefly, with the help of a diagram, the role of the two important processes involved in the formation of a p−n junction. (b) Name the device which is used as a voltage regulator. Draw the necessary circuit diagram and explain its working.
How can electrical conductivity of metals, insulator and semiconductors be explained qualitatively?
What is the use of a Zener diode?
With the help of a diagram, show how you can use several NAND gates to obtain an OR gate.
Write the names of two universal logic gates. What is integrated circuit? Write two advantages of it.
An incandescent lamp is operated at 240V and the current is 0.5A. What is the resistance of the lamp?
Write the names of logic gates related to figure P and table Q. Table:Q
A
B
Y
Y′
0
0
0
1
0
1
1
0
1
0
1
0
1
1
1
0
Find the output F of the logic circuit given below.
Draw the circuit diagram of a voltage regulator using zener diode.
(a) NAND gates are also called universal gate. Why? (b) Draw a logic symbol of OR gate. (c) Write the value of output y in the given circuit: (d) Write the name of the diode used in voltage regulation.
In which bias can a zener diode be used as voltage regulator?
What are universal gates? Why are they called so ?
A light bulb is rated at 100W for a 220V supply. Find the resistance of the bulb.
Write the logic symbol and truth table of NAND gate.
How will you obtain OR, AND gates from the NAND and NOR gates? Write symbol, Boolean formula and truth table.
By using Bolean Algebra prove that ˉAB+AˉB+AB=A+B.
In the given logic circuit, name the logic gates 1 and 2 . (a) Write the name of the combination of the gates.
Explain the formation of energy bands in solids. On the basis of energy bands distinguish between a metal, a semiconductor and an insulator.
How is Zener diode used as voltage regulator?
Draw a diagram of show how NAND gates can be combined to obtain an OR gate.(Truth table is not required).
What is optoelectronic junction devices? Write any two names of optoelectronic junction devices.
Draw separate energy band diagrams for conductors, semi-conductors and insulators and label each of them.
What is the output of the combination?
100\ mg mass of nichrome metal is drawn into a wire of area of cross-section 0.05{mm}^{2}. Calculate the resistance of this wire. Given density of nichrome 8.4\times {10}^{3}kg{m}^{-3} and resistivity of the material as \rho =1.2\times { 10 }^{ -6 }\Omega m.
If the measured value of resistance R = 1.05 \Omega wire diameter d = 0.60 mm, and length l = 75.3 cm, then find the maximum permissible error in resistivity, \rho = \frac{R(\pi d^2 /4)}{l}
Mention practical importance of Zener diode in a laboratory.
In a zener-regulated power supply a zener diode with V_{z}=6 volt is used for regulation. The load current is to be 4\ mA and the unregulated input is 10 volt. What should be the value of series resistor R_{s} if the current through diode is five times the load current?
Find out output for given logic gate:
The figure shows the input waveforms A and B for 'AND' gate. Draw the output waveform and write the truth table for this logic gate.
Three resistors each of 2 \Omega are connected together so that their total resistance is 3 \Omega. Draw a diagram to show this arrangement and check it by calculation.
What is internal resistance and ideal voltmeter?
Draw energy band diagrams of n -type and p -type semiconductors at temperature \mathrm { T } > 0 K. Mark the donor and acceptor energy levels with their energies .
Given the ratio of the numbers of holes and the number of conduction electrons in an intrinsic semiconductor.
(a) What are logic gates? (b) Draw a circuit diagram for dual-input AND Gate by using two diodes.
Why are NOR gates considered as universal gates?
Draw the symbol of NAND gate and write down truth table for this. Why is it called a universal gate?
The circuit shown below is working as a 8\ V\ dc regulated voltage source. When 12\ V is used as input, the power dissipated (in mW) in each diode is; (considering both zener dioses are identical)____________
Let \Delta \,E denote the energy gap between the valence band and the conduction band. The population of conduction electrons (and of the holes) is roughly proportional to e^{-\Delta \, E /2kT}. Find the ratio of the concentration of conduction electrons in diamond to that in silicon at a room temperature 300 K. \Delta \,E for silicon is 1\cdot1\, eV and for diamond is 6\cdot 0\, eV.
The output of a 2-input AND gate is fed to a NOT gate. Give the name of the combination and its logic symbol. Write down its truth table.
Write the truth table for the logic circuit shown below and identify the logic operation performed by this circuit.
Draw the necessary energy band diagrams to distinguish between conductors, semiconductors and insulators. How does the change in temperature affect the behaviour of these materials ? Explain briefly.
Using truth table of AND gate and NOT gate , show that NAND gate is an AND gate followed by a NOT gate. Hence write the truth table of NAND gate. Why are NAND gates called 'Universal Gates' ?
The following table gives the output of a two input logic gate. If the output of this gate is fed as input to a NOT gate, name the new logic gate so formed.
A
B
Y
0
0
1
1
0
1
0
1
1
1
1
0
Write the truth table for the circuit shown in figure. Name the gate that the circuit resembles.
Identify the logic gate represented by the following circuit by writing its truth table :
Answer the following questions. Show the output waveforms (Y) for the following inputs A and B of (i) OR gate (ii) NAND gate
Why is a Zener diode considered as a special purpose semiconductor diode ? Draw the I-V characteristics of a Zener diode and explain briefly how reverse current suddenly increases at the breakdown voltage. Describe briefly with the help of a circuit diagram how a Zener diode works to obtain a constant dc voltage from the unregulated dc output of a rectifier.
Explain how a Zener diode maintains a constant voltage across a load.
In an intrinsic semiconductor the energy gap E_g is 1.2\ eV. Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at 600\ K and that at 300\ K? Assume that the temperature dependence of intrinsic carrier concentration n_i is given by n_i = n_o exp \left(- \dfrac{E_g}{2 k_B T} \right) Where n_0 is a constant.
What happens to the potential barrier of a p-n junction diode when it is?
Draw the circuit diagram of OR-gate using diodes.
Explain the variation of conductivity with temperature for (i) a metallic conductor (ii) Ionic conductors and (iii) semiconductors
Sn,C and Si,Ge are all group XIV elements. Yet, Sn is a conductor, C is an insulator while Si and Ge are semiconductors. Why?
Draw the circuit used for voltage regulation in a Zener diode and also explain its process in short.