ELECS COACHING VOLUME 3 PART 2
Electronics & Semiconductor Knowledge Quiz
Test your knowledge on electronics and semiconductor concepts with this comprehensive quiz designed for students, professionals, and enthusiasts alike. With 101 carefully crafted questions, you'll explore various topics that range from basic semiconductor properties to complex IC characteristics.
Challenge yourself with:
- Multiple-choice questions
- Coverage of various electronics topics
- Immediate feedback on your answers
At room temperature a semiconductor material is:
Perfect insulator
Slightly conducting
Conductor
Any of the choices
If conductance increases as temperature increases, this is known as a:
Negative current flow
Positive coefficient
Positive resistance
Negative coefficient
Which of the following is not an arithmetic instruction?
ROL (rotate left)
DEC (decrement)
CMP (compare)
INC (increment)
The first Intel microprocessor to contain on-board cache memory was the ________.
Pentium Pro
80486
Pentium
80386
Which of the following logic families has the shortest propagation delay?
AS-TTL
HS-TTL
S-TTL
HCMOS
Which of the following has highest conductivity?
Platinum
Aluminum
Tungsten
Silver
The value of α in a transistor:
Is about 0.4
Is about 0.1
Is less than 1 but more than 0.9
Is always equal to 1
Which of these has highly doped p and n region?
PIN diode
Photodiode
Tunnel diode
Schottky diode
The depletion layer around p-n junction in JFET consists of:
Hole
Electron
Immobile charges
None of the choices
If the reverse voltage across a p-n junction is increased three times, the junction capacitance:
Will decrease
Will decrease by an approximate factor of about 2
Will increase by an approximate factor of about 2
Will increase
What is the static charge that can be stored by your body as you walk across a carpet?
The two series cannot be interfaced without the use of special interface buffers designed for that purpose, such as the open-collector buffers.
As long as the CMOS supply voltage is 5 V, they can be interfaced; however, the fan-out of the CMOS is limited to two TTL gates.
A 5 V Zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates.
A dropping resistor must be used on the CMOS 12 V supply to reduce it to 5 V for the TTL.
Which statement is false as regards holes?
Holes and electrons recombine
Holes exist only in semiconductors
Holes constitute positive charges
Holes exist in conductors as well as semiconductors
What are the major differences between the 5400 and 7400 series of ICs?
The 7400 series are an improvement over the original 5400s.
The 7400 series was originally developed by Texas Instruments. The 5400 series was brought out by National Semiconductors after TI`s patents expired, as a second supply source.
The 5400 series are military grade and require tighter supply voltages and temperatures.
The 5400 series are military grade and allow for a wider range of supply voltages and temperatures.
Which of the logic families listed below allows the highest operating frequency?
74AS
HCMOS
ECL
54S
Which of the following statements apply to CMOS devices?
The devices should be stored and shipped in antistatic tubes or conductive foam.
The devices should not be inserted into circuits with the power on.
All tools, test equipment, and metal workbenches should be tied to earth ground.
All of the choices.
What causes low-power Schottky TTL to use less power than the 74XX series TTL?
The Schottky-clamped transistor
Using NAND gates
Nothing. The 74XX series uses less power.
A larger value resistor
Which of the following devices has a silicon dioxide layer?
NPN transistor
MOSFET
Tunnel diode
JFET
The concentration of minority carriers in a semiconductor depends mainly on:
The extent of doping
The applied bias
Temperature
None of the choices
Which of the figures given below represents a NOR gate?
D
C
B
A
Which of the following logic families has the highest maximum clock frequency?
AS-TTL
S-TTL
HS-TTL
HCMOS
Assertion (A): Silicon is preferred over germanium in manufacture of semiconductor devices.
Reason (R): Forbidden gap in silicon is more than that in germanium.
Both A and R are true but R is not a correct explanation of A
A is false but R is true
A is true but R is false
Both A and R are true and R is correct explanation of A
In a piezoelectric crystal, applications of a mechanical stress would produce:
Magnetic dipoles in the crystal
Plastic deformation of the crystal
Electrical polarization in the crystal
Shift in the Fermi level
Which of the following summarizes the important features of ECL?
Poor noise immunity, positive supply voltage operation, good low frequency operation, and low power
Slow propagation time, high frequency response, low power consumption, and high output voltage swings
Low noise margin, low output voltage swing, negative voltage operation, fast, and high power consumption
Good noise immunity, negative logic, high frequency capability, low power dissipation, and short propagation time
For BJT transistor. The maximum power dissipation is specified as 350 mW if ambient temperature is 25°C. If ambient temperature is 60°C the maximum power dissipation should be limited to about:
600 mW
100 mW
450 mW
250 mW
When a reverse bias is applied to a p-n junction, the width of depletion layer.
May increase or decrease
Remains the same
Increases
Decreases
In which of the following is the width of junction barrier very small?
Tunnel diode
PIN diode
Photo diode
Schottky diode
Which of the following logic families has the highest noise margin?
LS TTL
TTL
CMOS
HCMOS
In an n-channel JFET,
I_D, I_S and I_G are considered positive when flowing into the transistor
I_D and I_S are considered positive when flowing into transistor and I_G is considered positive when flowing out of it
I_D, I_S, I_G are considered positive when flowing out of transistor
I_S and I_G are considered positive when flowing into transistor and I_D is considered positive when flowing out of it
When a p-n-p transistor is properly biased to operate in active region the holes from emitter.
Recombine with electrons in emitter
Diffuse through base into collector region
Recombine with electrons in base
None of the choices
From the given circuit below, we can conclude that:
Not possible to determined
BJT is pnp
BJT is npn
Transistor is faulty
Assertion (A): Two transistors one n-p-n and the other p-n-p are identical in all respects (doping, construction, shape, size). The n-p-n transistor will have better frequency response.
Reason (R): The electron mobility is higher than hole mobility.
Both A and R are true and R is correct explanation of A
A is false but R is true
A is true but R is false
Both A and R are true but R is not a correct explanation of A
Assertion (A): A decrease in temperature increases the reverse saturation current in a p-n diode.
Reason (R): When a diode is reverse biased surface leakage current flows.
Both A and R are true and R is correct explanation of A
A is true but R is false
Both A and R are true but R is not a correct explanation of A
A is false but R is true
A Schottky diode clamp is used along with switching BJT for:
Reducing the power dissipation
Reducing the switching time
Increasing the value of β
Reducing the base current
What is the static charge that can be stored by your body as you walk across a carpet?
3,000 volts
30,000 volts
Over 30,000 volts
300 volts
A diode is operating in forward region and the forward voltage and current are v = 3 + 0.3 sin ωt (volts) and I = 5 + 0.2 sin ωt (mA). The average power dissipated is:
About 15 mW
1.5 mW
15 mW
About 1.5 mW
In a piezoelectric crystal, application of a mechanical stress would produce:
Electric polarization in the crystal
Magnetic Dipoles in the crystal
Plastic deformation of the crystal
Shift in the Fermi level
The logic gate that will have HIGH or "1" at its output when any one of its inputs is HIGH is a(n):
AND gate
NOT operation
NOR gate
OR gate
What must be done to interface TTL to CMOS?
A pull-up resistor must be used between the TTL output-CMOS input node and Vcc; the value of RP will depend on the number of CMOS gates connected to the node.
As long as the CMOS supply voltage is 5 V, they can be interfaced; however, the fan-out of the TTL is limited to five CMOS gates.
A dropping resistor must be used on the CMOS 12 V supply to reduce it to 5 V for the TTL.
A 5 V Zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates.
Refer to the given figure. This circuit is known as:
A Hartley oscillator
A Clapp oscillator
An Armstrong oscillator
A Colpitts oscillator
The carriers of n channel JFET are:
Free electrons or holes
Free electrons
Holes
Free electrons and holes
Which of the following will not normally be found on a data sheet?
Maximum LOW level output voltage
Minimum HIGH level output voltage
Maximum HIGH level input current
Minimum LOW level output voltage
Why is the fan-out of CMOS gates frequency dependent?
Each CMOS input gate has a specific propagation time and this limits the number of different gates that can be connected to the output of a CMOS gate.
The input gates of the FETs are predominantly capacitive, and as the signal frequency increases the capacitive loading also increases, thereby limiting the number of loads that may be attached to the output of the driving gate.
The higher the number of gates attached to the output, the more frequently they will have to be serviced, thus reducing the frequency at which each will be serviced with an input signal.
When the frequency reaches the critical value, the gate will only be capable of delivering 70% of the normal output voltage and consequently the output power will be one-half of normal; this defines the upper operating frequency.
Which of these has degenerate p and n materials?
PIN diode
Zener diode
Photo diode
Tunnel diode
The drain characteristics of JFET in operating region, are:
Inclined upwards or downwards
Inclined upwards
Almost flat
Inclined downwards
When a p-n junction is forward biased:
The majority carriers move away from the junction
The current is very small
The width of depletion layer decreases
The width of depletion layer increases
What type of circuit is shown below, and how is the output ordinarily connected?
It represents an active-LOW inverter and is used in negative logic systems.
Any of the above could be correct, depending on the specific application involved.
It is an open-collector gate. An external load must be connected between the output terminal and an appropriate supply voltage.
It is an open-collector gate and is used to drive loads that cannot be connected directly to V_cc due to high noise levels.
As temperature increases:
The forbidden energy gap in silicon and germanium increase
The forbidden energy gap in silicon decreases while that in germanium decreases
The forbidden energy gap in silicon increases while that in germanium decreases
The forbidden energy gap in silicon and germanium decrease
Which material may also be considered a semiconductor element?
Ceramic
Carbon
Argon
Mica
Refer to the given figure. This circuit is known as:
A Colpitts oscillator
A Clapp oscillator
A Hartley oscillator
An Armstrong oscillator
A "floating" TTL input may be defined as:
Unused input that is not connected.
Unused input that is tied to the ground.
Unused input that is tied to V_cc through a 1 k resistor.
Unused input that is tied to used inputs.
A logic signal experiences a delay in going through a circuit. The two propagation delay times are defined as:
T_DLH and t_DHL.
T_LDH and t_HDL.
T_PLH and t_PHL.
T_HPL and t_LPH.
The Q point on a load line may be used to determine:
V_CC
V_B
V_C
I_C
Whenever a totem-pole TTL output goes from LOW to HIGH, a high-amplitude current spike is drawn from the V_cc supply. How is this effect corrected to a digital circuit?
By connecting a capacitor from V_out to ground
By using a switching power supply
By connecting a large resistor from V_cc to V_out
By connecting a radio-frequency capacitor from V_cc to ground.
Which is not an operand?
Assembler
Variable
Memory location
Register
Which bus is bidirectional?
Address bus
Control bus
Data bus
None of the choices
Voltage-divider bias provides:
An unstable Q point
A stable Q point
A Q point that easily varies with changes in the transistor`s current gain
A Q point that is stable and easily varies with changes in the transistor`s current gain
For a C-C configuration to operate properly, the collector-base junction should be reverse biased, while forward bias should be applied to which junction?
Cathode-anode
Base-emitter
Collector-base
Collector-emitter
With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be:
Low resistance
Infinite
High resistance
Open
Polled I/O works best when ________.
The polling rate is below 1000 s
There are no priority considerations
The polling rate exceeds 1000 s
Priority considerations are frequent
With interrupt-driven I/O, if two or more devices request service at the same time, ________.
The device closest to the CPU gets priority
The device assigned the highest priority is serviced first
The device that is fastest gets priority
The system is likely to crash
What is unique about TTL devices such as the 74S00?
The S denotes the fact that a single gate is present in the IC rather than the usual package of 2–6 gates.
The devices use Schottky transistors and diodes to prevent them from going into saturation; this results in faster turn on and turn off times, which translates into higher frequency operation.
The S denotes a slow version of the device, which is a consequence of its higher power rating.
The gate transistors are silicon (S), and the gates therefore have lower values of leakage current.
The C-B configuration is used to provide which type of gain?
Resistance
Voltage
Power
Current
Which of the following was not a design improvement for the 8086/8088 over the 8085?
Execution unit (EU)
Arithmetic logic unit (ALU)
16-bit data bus
Bus interface unit (BIU)
What is occurring when two or more sources of data attempt to use the same bus?
Bus contention
PPI
Bus interruption
Direct memory access
What type of circuit is represented in the given figure, and which statement best describes its operation?
It is an active LOW buffer, which can be turned on and off by the ENABLE input.
It is a tristate inverter. When the ENABLE input is HIGH, the output is effectively an open circuit—it is neither LOW nor HIGH.
It is a programmable inverter. It can be programmed to function as either an active LOW or an active HIGH inverter.
None of the choices.
The bipolar TTL logic family that was developed to increase switching speed by preventing transistor saturation is:
Emitter-coupled logic (ECL).
Current-mode logic (CML).
Emitter-coupled logic (ECL) and transistor-transistor logic (TTL).
Transistor-transistor logic (TTL).
What is the increase in switching speed between 74LS series TTL and 74HC/HCT (High-Speed CMOS)?
50
10
100
5
Which of the following is not an 8086/8088 general-purpose register?
Data segment (DS)
Address segment (AS)
Stack segment (SS)
Code segment (CS)
The first microprocessor had a(n)________.
2-bit data bus
8-bit data bus
1-bit data bus
4-bit data bus
What type of logic circuit is shown below and what logic function is being performed?
It is a CMOS NOR gate.
It is a PMOS NAND gate.
It is a CMOS AND gate.
It is an NMOS AND gate.
To operate properly, a transistor's base-emitter junction must be forward biased with reverse bias applied to which junction?
Base-emitter
Collector-emitter
Base-collector
Collector-base
Which is not part of the execution unit (EU)?
General registers
Arithmetic logic unit (ALU)
Flags
Clock
A transistor may be used as a switching device or as a:
Rectifier
Tuning device
Variable resistor
Fixed resistor
Which of the following is not a computer bus?
Control bus
Timer bus
Data bus
Address bus
The Pentium microprocessor has a data bus of ________.
16 bits
32 bits
64 bits
128 bits
Which of the following is not a computer functional block?
Memory
Input/output ports
Central-processing unit
Analog-to-digital converter
Refer to the figure given below. What type of device is shown and what input levels are required to turn the LED off?
The device is a Schottky AND gate and requires only one low input to turn the LED off.
The device is a Schottky open-collector AND gate and requires a low on both inputs to turn the LED off.
The device is an open-collector AND gate and requires only one low input to turn the LED off.
The device is an open-collector AND gate and requires both inputs to be HIGH in order to turn the LED off.
A transistor has a b_DC of 250 and a base current, I_B, of 20 µA. The collector current, I_C, equals:
50 mA
5 A
5 mA
500 µA
Which method bypasses the CPU for certain types of data transfer?
Interrupt-driven I/O
Software interrupts
Polled I/O
Direct memory access (DMA)
What does ECL stand for?
It stands for emitter-coupled logic; all of the inputs are coupled into the device through the emitters of the input transistors.
It stands for energy-coupled logic; the input energy is amplified by the input transistors and allows the device to deliver higher output currents.
It stands for electron-coupled logic; all of the devices used within the gates are N-type transistors.
It stands for emitter-coupled logic; all of the emitters of the input transistors are connected together and each transistor functions as an emitter follower.
The ends of a load line drawn on a family of curves determine:
Saturation and cutoff
The power curve
The operating point
The amplification factor
Which of the following is not a jump instruction?
JA (jump above)
JMP (unconditional jump)
JB (jump back)
JO (jump if overflow)
With low-power transistor packages, the base terminal is usually the:
Right end
Tab end
Middle
Stud mount
Refer the given figure. Which of the following describes the operation of the circuit?
A HIGH input turns Q1, Q2, and Q4 on; Q3 is off.
A LOW input turns Q1 and Q3 on; Q2 and Q4 are off.
A LOW input turns Q1 and Q4 off; Q2 and Q3 are on.
A HIGH input turns Q1, Q2, and Q3 off, and Q4 is on.
DMA is particularly suited for data transfer between the ________.
Disk drive and I/O
Disk drive and ROM
Disk drive and RAM
Disk drive and CPU
When transistors are used in digital circuits they usually operate in the:
Active region
Breakdown region
Linear region
Saturation and cutoff regions
A port can be ________.
Strictly for output
Strictly for input
Bidirectional
All of the choices
The IEEE/ANSI notation of an internal underlined diamond denotes:
Quadrature amplifiers.
Open-collector outputs.
Totem-pole outputs.
Tristate buffers.
A current ratio of I_C/I_E is usually less than one and is called:
Alpha
Theta
Beta
Omega
A P-N junction mimics a closed switch when it:
Has a low junction resistance
Cannot overcome its barrier voltage
Has a wide depletion region
Is reverse biased
The process of jointly establishing communication is called ________.
Handshaking
Bidirectional addressing
DMA
Multiplexing
Which of the following is not an enhancement to the Pentium that was unavailable in the 8086/8088?
Inclusion of an internal math coprocessor
Pipelined architecture
Expansion of cache memory
Data/address line multiplexing
A 20-bit address bus can locate ________.
4,194,304 locations
1,048,576 locations
8,388,608 locations
2,097,152 locations
Which of the following is not a basic element within the microprocessor?
Control unit
Arithmetic logic unit (ALU)
Register array
Microcontroller
Three different Q points are shown on a dc load line. The upper Q point represents the:
Intermediate current gain
Maximum current gain
Minimum current gain
Cutoff point
Which microprocessor has multiplexed data and address lines?
8086/8088
Pentium
80386
80286
During a read operation the CPU fetches ________.
Another address
A program instruction
Data itself
All of the choices
A collector characteristic curve is a graph showing:
Collector current (I_C) versus collector-emitter voltage (V_CC) with (V_BB) base bias voltage held constant
Emitter current (I_E) versus collector-emitter voltage (V_CE) with (V_BB) base bias voltage held constant
Collector current (I_C) versus collector-emitter voltage (V_CE) with (V_BB) base bias voltage held constant
Collector current (I_C) versus collector-emitter voltage (V_C) with (V_BB) base bias voltage held constant
The Pentium can address ________.
1 MB
4 GB
1 GB
2 GB
In a C-E configuration, an emitter resistor is used for:
Higher gain
Stabilization
Collector bias
Ac signal bypass
RATE!
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