## Digital Electronics MCQs1) Which number system has a base 16 - Hexadecimal
- Octal
- Binary
- Decimal
2) What is a digital-to-analog converter? - It stores digital data on the computer.
- It converts alternating current (AC) into direct current (DC).
- It converts electrical power into mechanical power.
- It takes the digital data from an audio CD and converts it to a useful form.
3) The following hexadecimal number (1E.43)16 is equivalent to - (36.506)
_{8} - (36.206)
_{8} - (35.506)
_{8} - (35.206)
_{8}
If you want to convert a hexadecimal number into an octal number, the first thing you need to do is convert a hexadecimal number into binary form by writing the binary equivalent of each digit in the form of 4 bits. Once you write the number into binary form, you need to group the binary equivalent in 3 bits, then for each of the three bits, the respective digit is written. (1E.43) = (00011110.01000011) = (011110.010000110) = (011 110.010 000 110) = (36.206) 4) How many entries will be in the truth table of a 4-input NAND gate? - 6
- 8
- 32
- 16
A NAND gate is a universal logic gate that performs the negation (NOT) of an AND logic operations in digital circuits. As we know, Y = 2 Where, n = number of inputs. 5) How many bits are needed to store one BCD digit? - 2 bits
- 4 bits
- 3 bits
- 1 bit
6) Convert (312) - (201)
_{10} - (202)
_{10} - (203)
_{10} - (204)
_{10}
Octal to decimal conversion is usually obtained by multiplying 8 to the power of base along with the value at the index position. (312) = 192 + 8 +2 = (202) 7) A SCR (Silicon Controlled Rectifier) is a - Device with 3 junctions
- Device with 2 junctions
- Device with 1 junction
- Device with 4 junctions
8) Which semiconductor device is not a current triggering device? - TRIAC
- MOSFET
- GTO
- Thyristor
9) Which of these sets of logic gates are known as universal gates? - XOR, NAND, OR
- OR, NOT, XOR
- NOR, NAND, XNOR
- NOR, NAND
10) What is the addition of the binary number 101001+ 010011=? - 010100
- 111100
- 000111
- 101110
0 + 1 = 1 1 + 0 = 1 0 + 0 = 0 1 + 1 = 0 (with carry 1) 101001+ 010011 = 111100 11) What is the binary subtraction of 101001 - 010110 =? - 010011
- 100110
- 011001
- 010010
1 - 0 = 1 0 - 1 = 1 (With borrow 1) 0 - 0 = 0 1 - 1 = 0 therefore, the subtraction of 101001 - 010110 = 010011 12) What is the binary multiplication of 10100 * 01011 =? - 011011000
- 011001100
- 011011100
- 011100011
1 * 0 = 0 0 * 1 = 0 0 * 0 = 0 1 * 1 = 1 therefore, the multiplication of 10100 - 01011 = 011011100 13) Divide the binary number: 111001 � 1101 and find the reminder - 1010
- 0110
- 0101
- 0011
If you want to divide any binary number, you need to know the binary division rule. The binary division is accomplished using the long division rule. Therefore, the remainder of 111001 ÷ 1101 = 0101 14) In the toggle mode, a JK flip-flop has - J = 0, K = 1
- J = 1, K = 1
- J = 0, K = 0
- J = 1, K = 0
15) A classification of integrated circuits with complexities of 30 to 300 equivalent gates on a single chip is known as? - VLSI
- SSI
- LSI
- MSI
In In In SSI (Small-Scale Integration) = In VLSI (Very Large-Scale Integration) = 16) The inverter can be classified as - Power Inverter
- Voltage source Inverter
- Current source Inverter
- Both option b and c
Inverter refers to an electronic device that converts direct current (DC) to alternating current (AC). It has a wide range of applications for small appliances, TVs, DVD players, computer power supply to large electric power supply like photovoltaic solar cells. Based on the type of the input source, Inverters are divided into two categories. **Current source inverters:**In current source inverters, the input is a current source.**Voltage source inverters:**In voltage source inverters, the input is a voltage source.
17) Temperature variation is a/an - Analog quantity
- Digital quantity
- Either Analog or Digital quantity
- None of these
18) 1's complement of 1011001 is - 0100111
- 0101100
- 0100110
- 0110110
If you want to calculate 1's complement of any binary number, you need to reverse its binary bits. All the 0's to 1's and 1's to 0's. Therefore, 1's complement of 1011001 = 0100110 19) 2's complement of 1011011 is - 0100011
- 0110101
- 0100011
- 0100101
2's complement of 1011011 = 0100100 + 1 = 0100101. 20) An overflow is a - User input problem
- Hardware problem
- Software problem
- Input-Output problem
21) A digital circuit that can store only one bit is a - Register
- NOR gate
- Flip-flop
- XOR gate
22) The excess-3 code for 584 is given by - 100010110111
- 100001110111
- 100010010110
- 100001010110
23) In Digital electronics (Boolean algebra), the OR operation is performed by which of the given properties - Distributive properties
- Commutative properties
- Associative properties
- All of these
In Boolean algebra, the distributive properties are given by the following equation:
In Boolean algebra, the commutative properties are given by the following equation:
In Boolean algebra, the distributive properties are given by the following equation:
24) The queue is also known as - Flash memory
- FILO memory
- Flash memory
- FIFO memory
25) In three-phase half-wave rectifier, each diode conducts for a duration of - 120
^{0} - 90
^{0} - 180
^{0} - 60
^{0}
26) DeMorgan's Law states that - (A+B)' = A'*B
- (AB)' = A' + B'
- (AB)' = A' + B
- (AB)' = A + B
27) The logical sum of two or more than two logical products is termed as - OR operation
- POS
- SOP
- NAND operation
28) The Minterms for four variables - 8
- 16
- 2
- 1
Minterms is given by the following formula
Therefore, 2 29) A K-map (Karnaugh map) is an abstract form of which diagram organized as a squares matrix. - Block diagram
- Cycle diagram
- Square diagram
- Venn diagram
30) Which of the given device used in speed control of a DC motor? - NPN transistor
- PNP transistor
- FET
- SCR
31) One nibble is equal to how many bits - 4
- 2
- 16
- 8
32) Suppose the output of an XNOR gate is 1. Which of the given input combination is correct? - A = 0, B' = 1
- A = 1, B = 1
- A = 0, B = 1
- A = 0, B = 0
An XNOR refers to a digital logic gate with two or more inputs and one output that executes logical equality. The output of an XNOR gate is true either all of its inputs are true, or all of its inputs are false. When one of its inputs is false, and others are true, then the output is false. The output of the XNOR gate is given by the following equation.
33) In DTL, the logic gating function is performed by - Inductor
- Diode
- Transistor
- Transformer
34) Which of the given logic family provide minimum power dissipation - JFET
- ECL
- CMOS
- TTL
35) The AND operation is equivalent to - Union
- Intersection
- Division
- Both option a and b
36) TTL is a class of digital circuits built from - Resistors only
- BJT (Bipolar Junction Transistors) only
- JEFT only
- Both option a and b
37) Which logic unit is the fastest of all the logic families? - DTL
- TTL
- ECL
- CMOS
ECL stands for Emitter Coupled Logic. It is the fastest of all the logic families because of its higher transmission rate.
- The storage time is removed as the transistors are utilized in different amplifier mode and are never driven into saturation.
- It is the fastest logic family and has the minimum propagation delay.
- Power dissipation is basically 10nw per gate, relying on the power supply voltage, output load etc.
- The CMOS components are usually expensive, but CMOS technology is cost-efficient.
- It has high input impedance.
- Power dissipation is basically 10nw per gate.
- Cost-efficient components.
- The possibility of damage to the equipment is less from electrostatic charge as compared to CMOS.
38) Positive integers must be represented by - Signed numbers
- Unsigned numbers
- Both option a and b
- None of the above
39) The Ward- Leonard system is used for controlling the speed of - Three-phase AC motors
- Universal motors
- Induction motors
- DC motors
40) When the PIV rating of a diode is exceeded - The diode behaves like a thyristor.
- The diode behaves like a resistor.
- The diode is destroyed.
- The diode behaves like a tunnel diode.
We usually select the PIV larger than the largest normal reverse operating voltage in our circuit. If you are making a full-wave rectifier for 220 Vac, you'd typically select a diode with a 240 or more PIV to give some "head room" and "safety factor" on the diode. The minimum should usually be selected like this: round-up from your designed or simulated reverse voltage to the next higher PIV for a diode family that gives you the current you require. 41) Which insulating layer is used in the fabrication of MOSFET? - Silicon Nitride
- Aluminum sulphate
- Copper sulphate
- Silicon dioxide
42) CMOS technology used in? - Microprocessor
- Inverter
- Digital logic
- Both option a and c
43) The basic building blocks of the arithmetic logic unit in digital computers are known as - Adders
- Attenuator
- Demultiplexer
- Subtractors
The basic building blocks of the arithmetic unit in digital computers are known as adders. Adder is the Arithmetic mathematical function derived out of Logic gates. So, Adder always plays a major role in understanding Digital Electronics. The simplest but the most powerful application of logic gates is Adder. A full adder is similar to a half adder except that instead of 2 inputs and two outputs, there are now three inputs and two outputs. The inputs are carry-in (C A half adder is typically only useful for " 44) The number of inputs in a half adder is? - 8
- 2
- 11
- 32
45) Why is a decoder used in digital electronics? - To convert non coded information into a binary coded form.
- To convert coded information into a non-coded form.
- It is used to divide address bus and data bus.
- None of these
46) How much input and output needed for demultiplexer? - Many outputs to one input
- One input many outputs
- One input one output
- None of these
47) A register can be defined as - The group of transistors for storing n- a bit of information
- The group of transistors for storing two bits of information
- The group of flip-flops for storing n bit of information
- The group of flip-flops for storing binary information.
48) The primary difference between a counter and a register is - A counter has the capability to store n bit of information whereas a register has one bit.
- A register counts data.
- A register has no specific sequence of states.
- A counter has no particular sequence of states.
The primary difference between a counter and a register is that register has no specific state sequence except in certain conditions. A counter is a special case of a register while the register has the same clock. generally, the register can only be stored, loaded, or used for the stack or as the program counter. The counter does not need to have the same clock.
49) What is the radix of the octal number system? - 2
- 10
- 8
- 16
50) Dual slop ADC has the value of R = 1 K? and the value of C is 0.44 nano-farad has charging and discharging time for some specific voltage is nine ns and 3 ns, respectively. If the reference voltage is 4.4 V, what is the peak voltage reached by a triangular wave during the charging process? - 300 mV
- 30 mV
- 3 mV
- 3 mV
51) The two-transistor model of the SCR is obtained by - Bisecting the SCRs top two and bottom two layers
- Bisecting the SCRs top two layers
- Bisecting the SCRs bottom two Layers
- Bisecting the SCRs diagonally
52) What is the main function of the filter in a rectifier circuit? - Maximize AC input variations
- To suppress odd harmonics.
- Remove ripples from the rectified output.
- Minimize DC input and AC output variations.
The main function of the filter in a rectifier circuit is to remove ripples from the rectified output. As we know, rectifiers are primarily used to convert alternating current (AC) to direct current (DC). There we find a considerable AC component in the output, which is called Many electronic systems require pure direct current supply to drive or power them. To make a efficient continuous power supply that gives pure DC output, we need to remove the AC component from the output of rectifiers. 53) What is the actual meaning of the parallel load of a shift register? - All flip-flops are set with data.
- It means a parallel shifting of data.
- All flip-flops are present with data.
- Each flip flop is loaded with data simultaneously.
54) In a 100 kHz clock frequency, 16 bits can be serially entered into a shift register? - 150 micro-sec
- 160 micro-sec
- 170 micro-sec
- 180 micro-sec
Given f = 100 kHz As we know, So, T = (1/100) m sec = 1/0.1 micro second = 10 micro sec; In serial transmission first the one- bit data enters at a time. After 16 clock cycles 16 bit will be loaded, it means = 16*10 = 160 micro-sec. 55) A series of equal space time pulses may be easily generated by which type of counter circuit? - Johnson shift
- Clock shift
- Binary shift
- Ring counter
56) At which frequency the digital data can be applied to a gate? - Run-time frequency
- Propagation Frequency
- Operating frequency
- AC frequency
57) What are the three output conditions of 3- state buffer? - High Impedance, 0, float
- Negative, positive, 0
- 1, Low Impedance, float
- High, Low, float
58) If a transistor has I - 1
- 7
- 9
- 11
In common emitter, the term
In the common base, DC gain α refers to the ratio of the collector current I The equation of dc current gain
Now, we can establish the relationship between α and β
Given
β = α/ (1 - α) = 2/ (1 - 2) β = -2 Here the negative value of β indicates its direction, because by convention positive current is always termed as flowing into the device. So, the current gain is negative. 59) In an 8 -bit Johnson counter sequence, how many states orbit patterns are possible? - 240
- 228
- 232
- 220
As we know, the total number of states in the Jhonson counter is determined by the given formula 2 Now, the total number of used states = 2N = 2* 8 = 16 therefore, the total number of unused states = 256-16 = 240 Next TopicDigital Electronics Tutorial |