A logic gate is an electronic circuit that performs a logical operation on one or more inputs to produce a single output. Logic gates like AND, OR, NOT, etc., are the building blocks of digital circuits.
Which logic gate produces a high output only when all inputs are high?
A OR
B AND
C NAND
D NOR
An AND gate produces a high (1) output only when all its inputs are high (1). If any input is low (0), the output will be low.
What is the output of a NOT gate if the input is 1?
A 0
B 1
C Depends on the input
D Undefined
A NOT gate inverts the input signal. If the input is 1, the output will be 0, and vice versa.
What is a flip-flop used for in digital circuits?
A Signal amplification
B Arithmetic operations
C Storing a single bit of data
D Analog-to-digital conversion
A flip-flop is a basic memory element in digital electronics that can store one bit of information, representing a binary state (0 or 1).
What is the function of a multiplexer (MUX)?
A To perform addition
B To select one input from multiple inputs
C To invert the signal
D To decode binary data
A multiplexer takes several input signals and forwards only one of them to the output based on a control signal.
Which Boolean algebra law states that A+A=A?
A Identity Law
B Idempotent Law
C Commutative Law
D Distributive Law
The Idempotent Law in Boolean algebra states that combining a variable with itself using OR (or AND) results in the same variable.
What is the purpose of a decoder in digital circuits?
A To store data
B To amplify signals
C To convert binary information into a more readable form
D To perform subtraction
A decoder converts coded inputs into coded outputs, where the output lines represent specific combinations of the input signals.
Which type of memory is non-volatile?
A RAM
B ROM
C SRAM
D DRAM
ROM (Read-Only Memory) retains data even when the power is turned off, making it non-volatile. It is typically used to store firmware.
What is the output of an XOR gate when both inputs are 1?
A 0
B 1
C Depends on the input
D Undefined
An XOR gate outputs 1 only when the inputs are different. If both inputs are the same (both 1 or both 0), the output is 0.
What is the purpose of a Karnaugh map in digital electronics?
A To simplify Boolean expressions
B To build circuits
C To design memory
D To test microcontrollers
A Karnaugh map is a visual representation of truth tables used to simplify Boolean expressions, minimizing the number of logic gates required.
Which digital component is used for division of frequency?
A Flip-Flop
B Multiplexer
C Encoder
D Counter
Counters can divide the frequency of a clock signal by counting cycles and producing an output at a slower rate.
What is the full form of FPGA?
A Field Programmed Gate Array
B Flexible Programmable Gate Array
C Fast Processing Gate Array
D Field Processor Gate Array
An FPGA is a type of programmable logic device used to implement digital circuits and can be reprogrammed to suit different applications.
What is a latch in digital electronics?
A A type of memory device that changes output based on the clock signal
B A device that stores binary information
C A device that amplifies signals
D A sequential circuit without a clock
A latch is a memory device that operates without a clock signal and changes output immediately when its input changes.
Which type of flip-flop is used to eliminate the race-around condition?
A SR Flip-Flop
B D Flip-Flop
C JK Flip-Flop with Master-Slave Configuration
D T Flip-Flop
The master-slave configuration in JK flip-flops ensures that input changes do not affect the output within the same clock cycle, eliminating the race-around condition.
What is propagation delay in digital circuits?
A Time taken to execute a program
B Time taken for a signal to travel through a logic gate
C Time taken to charge a capacitor
D Time taken for memory to access data
Propagation delay is the time interval between the application of an input signal and the corresponding change in output.
What is the primary difference between a microprocessor and a microcontroller?
A Microprocessor has internal memory, while microcontroller does not
B Microcontroller includes I/O ports and peripherals, while a microprocessor does not
C Microcontroller is faster than a microprocessor
D Both are the same
Microcontrollers are self-contained systems with integrated peripherals, whereas microprocessors require external components for I/O and memory.
Which of the following is used for digital-to-analog conversion?
A ADC
B DAC
C RAM
D ROM
A Digital-to-Analog Converter (DAC) converts digital binary data into an analog signal.
What is the main function of a clock signal in sequential circuits?
A To amplify signals
B To simplify Boolean expressions
C To store data
D To synchronize circuit operations
The clock signal provides timing pulses that control the sequential changes in a digital circuit.
What is the purpose of a Verilog language?
A To program software
B To design digital circuits
C To test memory
D To convert analog signals to digital
Verilog is a hardware description language (HDL) used to model and simulate digital circuits.
Which digital logic testing technique uses test patterns to identify faults in circuits?
A Boundary Scan
B Fault Injection
C Built-In Self-Test (BIST)
D Propagation Delay Test
BIST is a self-testing mechanism embedded in digital circuits to automatically generate test patterns and detect faults.
What is the binary equivalent of the decimal number 10?
A 1000
B 1010
C 1100
D 1110
To convert decimal 10 to binary, divide the number by 2 and record the remainders. The binary equivalent is 1010.
Which logic gate has a high output when any of its inputs are high?
A AND
B OR
C XOR
D NOR
An OR gate produces a high (1) output if at least one of its inputs is high.
What is the purpose of a truth table in digital electronics?
A To amplify signals
B To simplify logic circuits
C To represent the output of a logic function for all possible inputs
D To design flip-flops
A truth table lists all possible input combinations and their corresponding outputs for a logic circuit.
How many inputs are required for a full adder?
A 2
B 3
C 4
D 1
A full adder has three inputs: two operands and a carry-in from the previous addition.
Which of the following is a sequential circuit?
A Multiplexer
B Decoder
C Flip-Flop
D Logic gate
Sequential circuits, such as flip-flops, have outputs that depend on current inputs and past outputs (stored state).
What is the output of a NAND gate when all inputs are 1?
A 1
B 0
C Undefined
D Depends on the inputs
A NAND gate produces the opposite output of an AND gate. If all inputs are 1, the output is 0.
What is the binary equivalent of the decimal number 255?
A 11111110
B 11111111
C 11110000
D 11111101
The binary equivalent of decimal 255 is 2^8 – 1, which equals 11111111.
What is the main characteristic of a combinational circuit?
A Outputs depend on past inputs
B Outputs depend only on current inputs
C It has a memory element
D It uses feedback loops
Combinational circuits compute outputs solely based on the present inputs without involving memory.
Which Boolean expression is simplified as A⋅0=0?
A Identity Law
B Nullification Law
C Idempotent Law
D Distributive Law
The Nullification Law states that any variable ANDed with 0 results in 0.
What is a register in digital electronics?
A A type of memory to store multiple bits of data
B A logic gate
C A counter
D A clock signal
A register is a group of flip-flops used to store data temporarily in digital systems.
How many states does a 3-bit counter have?
A 6
B 8
C 4
D 16
A 3-bit counter has 2^3 = 8 unique states, ranging from 000 to 111 in binary.
Which type of circuit is used for priority encoding?
A Encoder
B Decoder
C Multiplexer
D Demultiplexer
An encoder assigns a binary code to one active input among multiple inputs, with priority encoding resolving conflicts.
What is the resolution of a 4-bit ADC?
A 24
B 1/16
C 1/2
D 1/256
Resolution is 1/2^n, where n is the number of bits. For a 4-bit ADC, the resolution is 1/16.
What is the function of an ALU (Arithmetic Logic Unit)?
A To perform arithmetic and logical operations
B To store data
C To generate clock signals
D To convert data
An ALU performs mathematical (addition, subtraction) and logical (AND, OR, NOT) operations in digital systems.
What is the binary addition result of 1101 + 1011?
A 10010
B 11110
C 10110
D 10000
Perform binary addition. 1101 + 1011 = 10010.
Which flip-flop is called a data or delay flip-flop?
A JK Flip-Flop
B D Flip-Flop
C SR Flip-Flop
D T Flip-Flop
The D flip-flop captures and holds data with a single input, often referred to as the data or delay flip-flop.
What does VHDL stand for?
A Very High Digital Logic
B Virtual Hardware Description Language
C Very High-Speed Integrated Circuit Hardware Description Language
D Variable High-Level Logic
VHDL is a hardware description language used for designing and modeling digital systems.
Which device is used to convert an analog signal into a digital signal?
A DAC
B ADC
C RAM
D ROM
An Analog-to-Digital Converter (ADC) converts continuous analog signals into discrete digital values.
Which sequential device is used to divide a clock frequency by 2?
A Flip-Flop
B Multiplexer
C Decoder
D Counter
A flip-flop toggles its output state on each clock pulse, effectively dividing the clock frequency by 2.
What is the purpose of setup time in digital circuits?
A To amplify signals
B To ensure data is stable before the clock edge
C To store data
D To simplify Boolean expressions
Setup time is the minimum time before a clock edge during which the input signal must remain stable for proper operation.
Which logic gate is known as the universal gate?
A AND
B OR
C NAND
D XOR
The NAND gate is called a universal gate because it can be used to implement any other type of logic gate, including AND, OR, and NOT gates.
What is the decimal equivalent of the binary number 110111011101?
A 10
B 11
C 12
D 13
Binary 110111011101 is calculated as (1×2³)+(1×2²)+(0×2¹)+(1×2⁰)=13.
What is the output of an XNOR gate when both inputs are the same?
A 0
B 1
C Undefined
D Depends on inputs
An XNOR gate produces a high (1) output when both inputs are either 0 or 1, meaning they are the same.
Which Boolean algebra property is represented by A+B=B+A?
A Commutative Law
B Distributive Law
C Associative Law
D Absorption Law
The commutative property states that the order of variables does not affect the result of an OR or AND operation.
What is the primary function of a demultiplexer?
A Combine multiple inputs into one output
B Amplify the signal
C Divide one input into multiple outputs
D Store data
A demultiplexer takes a single input signal and distributes it to one of several outputs based on control signals.
What type of counter increments or decrements by one?
A Ring Counter
B Johnson Counter
C Up/Down Counter
D Asynchronous Counter
An up/down counter can increment (up) or decrement (down) its value by one, based on a control signal.
Which flip-flop is used in shift registers?
A D Flip-Flop
B JK Flip-Flop
C SR Flip-Flop
D T Flip-Flop
D flip-flops are commonly used in shift registers because they store and shift data in synchronization with clock pulses.
What is the purpose of a clock signal in synchronous circuits?
A To perform logical operations
B To control the speed of data processing
C To store data permanently
D To amplify signals
The clock signal ensures that all parts of the synchronous circuit operate in unison by providing a timing reference.
Which memory device loses data when power is turned off?
A ROM
B RAM
C Flash Memory
D EEPROM
RAM (Random Access Memory) is volatile memory that loses its stored data when the power supply is removed.
Which component is used for binary addition in a digital circuit?
A Multiplexer
B Decoder
C Half Adder
D Shift Register
A half adder performs the binary addition of two bits and produces a sum and carry output.