Q-What is Digital Electronics?
a) Field of electronics involving the study of digital signal
b) Engineering of devices that digital signal
c) Engineering of devices that produce digital signal
d) All pf the mentioned
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Answer: d
Explanation: Digital electronics is a branch of electronics concerned with the study of digital signals as well as the design of systems that use or generate them. For electronics, gadgets, and equipment, “boolean logic” and “discrete signal electronics” are used.
Q-Which of the following options comes under the non – saturated logic family in Digital Electronics?
a) Emitter – coupled Logic
b) High-Threshold Logic
c) Integrated – injection Logic
d) Diode – Transistor Logic
…………
Answer: a
Explanation: Bipolar IC’s can be classified as saturated and non – saturated logic families. ECL (Emitter – coupled Logic) and Schottky TTL are said to come under the non – saturated logic family.
Q-Which of the following digital logic circuits can be used to add more than 1 – bit simultaneously?
a) Full – adder
b) Ripple – carry adder
c) Half – adder
d) Serial adder
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Answer: b
Explanation: A Ripple – carry adder is a parallel binary adder in which the addition of more than 1 – bit data can be done simultaneously. The inputs to a parallel circuit can be sent and processed at once unlike series circuits in which inputs are sent one by one.
Q-Which of the following majorly determines the number of emitters in a TTL digital circuit?
a) Fan – in
b) Fan – out
c) Propagation delay
d) Noise immunity
…………
Answer: a
Explanation: The TTL circuit uses multi – emitter transistors with many emitters in the input. Thus, the number of emitters is determined by the fan – in. Fan – in determines the number of inputs the particular gate can handle.
Q-What are the basic gates in MOS logic family?
a) NAND and NOR
b) AND and OR
c) NAND and OR
d) AND and NOR
……….
Answer: a
Explanation: The MOS logic family uses the MOSFET devices to perform its operation. NAND and NOR are the basic gates that are the building blocks of most digital circuits.
Q-What value is to be considered for a “don’t care condition”?
a) 0
b) 1
c) Either 0 or 1
d) Any number except 0 and 1
………..
Answer: c
Explanation: A don’t care condition can take 0 or 1 according to the requirement. SOP expressions may consider it to be 1 to increase the number of 1s and POS expressions may consider it to be 0 to increase the number of 0s.
Q-What will a TTL digital circuit possess due to the presence of a multi – emitter transistor?
a) Smaller resistance
b) Larger area
c) Smaller area
d) Larger resistance
……….
Answer: c
Explanation: TTL circuit uses multi – emitter transistors. These transistors have a smaller area. As Capacitance is directly proportional to area, a smaller area leads to a lower capacitance.
Q-Which of the following options is a Current – Mode logic used in Digital Circuits?
a) TTL
b) RTL
c) ECL
d) IIC
………
Answer: c
Explanation: Emitter coupled logic or ECL is a Current – Mode logic. While operating in active mode, they help in eliminating the turn – off delay of saturated transistors. ECL family has a higher switching speed and dissipates more power
Q-Which of the following options are correct for a 4×1 multiplexer?
a) It has four 3 – input AND gates
b) It has four 2 – input AND gates
c) It has one 3 – input AND gate
d) It has one 3 – input AND gate
………..
Answer: a
Explanation: A 4 x 1 multiplexer has 2 select lines, 4 input lines, and 1 output line. AND gates are required to pass the inputs. Thus 4 AND gates will be used for each input. 3 – input AND gate is used, where 2 inputs come from each of the select lines and 1 input for the data
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