Q#1: What is a Half-Adder used for?
(A) To multiply two binary numbers
(B) To add two single-bit numbers
(C) To store one-bit data
(D) To convert binary to decimal
Answer: (B) To add two single-bit numbers
Q#2: What is the difference between BCD-to-Decimal Decoder and 4-to-16 Binary Decoder?
(A) BCD-to-Decimal Decoder has 10 output pins, Binary Decoder has 16
(B) BCD-to-Decimal Decoder has more inputs
(C) Binary Decoder works only for decimal numbers
(D) No difference
Answer: (A) BCD-to-Decimal Decoder has 10 output pins, Binary Decoder has 16
Q#3: What are the major uses of a decoder circuit?
(A) Arithmetic operations only
(B) Selection of peripheral devices and instruction decoding
(C) To store memory
(D) To implement flip-flops
Answer: (B) Selection of peripheral devices and instruction decoding
Q#4: How are PALs (Programmable Array Logic) numbers identified?
(A) By the number of inputs, output type, and polarity
(B) By voltage and frequency
(C) By the type of gates used
(D) By their memory size
Answer: (A) By the number of inputs, output type, and polarity
Q#5: In ABEL, which of the following is true?
(A) Variables are case insensitive
(B) All equations must end with “;”
(C) ABEL cannot define XOR gates
(D) ABEL is only used for simulation
Answer: (B) All equations must end with “;”
Q#6: What is the output of a 2-bit comparator when A=01 and B=10?
(A) A>B=1, A<B=0, A=B=0
(B) A>B=0, A<B=1, A=B=0
(C) A>B=0, A<B=0, A=B=1
(D) A>B=1, A<B=1, A=B=0
Answer: (B) A>B=0, A<B=1, A=B=0
Q#7: Why is using a 5-variable K-map not preferable?
(A) It requires more gates
(B) It becomes difficult to manage and simplify
(C) It only works for decimal numbers
(D) It is slower than binary adders
Answer: (B) It becomes difficult to manage and simplify
Q#8: Which section is NOT part of an ABEL module source file?
(A) Declarations
(B) Logic Descriptions
(C) Test Vectors
(D) Power supply
Answer: (D) Power supply
Q#9: What does a Tri-State Buffer do?
(A) Adds two binary numbers
(B) Multiplies two binary numbers
(C) Disconnects output from input when control line is low
(D) Stores one-bit data permanently
Answer: (C) Disconnects output from input when control line is low
Q#10: Why is a 2-bit comparator called a parallel comparator?
(A) It compares all bits simultaneously
(B) It works with serial inputs only
(C) It uses a special multiplier
(D) It outputs decimal values
Answer: (A) It compares all bits simultaneously
Q#11: What is the main use of a Demultiplexer?
(A) To add two binary numbers
(B) To connect a single input to multiple outputs
(C) To encode data
(D) To multiply two numbers
Answer: (B) To connect a single input to multiple outputs
Q#12: What is the difference between a 1-to-4 Demultiplexer and a 2-to-4 Decoder?
(A) Demux has a data input used as enable, decoder does not
(B) Demux has more outputs
(C) Decoder has fewer inputs
(D) No difference
Answer: (A) Demux has a data input used as enable, decoder does not
Q#13: Which of the following is true about a Half-Adder?
(A) 1 input bit, 1 output bit
(B) 2 input bits, 2 output bits
(C) 3 input bits, 2 output bits
(D) 2 input bits, 1 output bit
Answer: (B) 2 input bits, 2 output bits
Q#14: Which ABEL symbols correspond to NOT, AND, OR, XOR?
(A) NOT=!, AND=&, OR=#, XOR=$
(B) NOT=#, AND=!, OR=$, XOR=&
(C) NOT=&, AND=#, OR=!, XOR=$
(D) NOT=$, AND=!, OR=#, XOR=&
Answer: (A) NOT=!, AND=&, OR=#, XOR=$
Q#15: What is the advantage of low power consumption in circuits?
(A) Reduced battery life
(B) Reduced heat dissipation and allows compact design
(C) Slower switching
(D) Increased gate size
Answer: (B) Reduced heat dissipation and allows compact design