Digital Electronic/Circuits MCQs on “Multiplexers(Data Selectors)”.
1. 4 to 1 MUX would have ____________
A. 2 inputs
B. 3 inputs
C. 4 inputs
D. 5 inputs
Answer: C
2. The two input MUX would have ____________
A. 1 select line
B. 2 select lines
C. 4 select lines
D. 3 select lines
Answer: A
Clarification: The two input multiplexer would have n select lines in 2n. Thus n =1. Therefore, it has 1 select line.
3. A combinational circuit that selects one from many inputs are ____________
A. Encoder
B. Decoder
C. Demultiplexer
D. Multiplexer
Answer: D
Clarification: A combinational circuit that selects one from many inputs is known as Multiplexer. Whereas, a combinational circuit that divides one input into multiple outputs is known as Demultiplexer.
4. 4 to 1 MUX would have ____________
A. 1 output
B. 2 outputs
C. 3 outputs
D. 4 outputs
Answer: A
5. Which of the following circuit can be used as parallel to serial converter?
A. Multiplexer
B. Demultiplexer
C. Decoder
D. Digital counter
Answer: A
Clarification: A combinational circuit that selects one from many inputs is known as Multiplexer. In multiplexer, different inputs are inserted parallely and then it gives one output which is in serial form.
6. A combinational circuit is one in which the output depends on the ____________
A. Input combination at the time
B. Input combination and the previous output
C. Input combination at that time and the previous input combination
D. Present output and the previous output
Answer: A
Clarification: A combinational circuit is one in which the output depends on the input combination at the time, whereas, a sequential circuit is one in which the output depends on present input as well past outputs.
7. Without any additional circuitry an 8:1 MUX can be used to obtain ____________
A. Some but not all Boolean functions of 3 variables
B. All function of 3 variables but none of 4 variables
C. All functions of 3 variables and some but not all of 4 variables
D. All functions of 4 variables
Answer: D
Clarification: A 2^n:1 MUX can implement all logic functions of (n+1) variables without any additional circuitry. Thus 8:1 MUX can implement all logic functions of (3+1) variables, for 4 variables there are 16 possible combinations. So to use 8:1 MUX use 3 inputs as select lines of MUX and the 4th input as input of MUX.
8. A basic multiplexer principle can be demonstrated through the use of a ____________
A. Single-pole relay
B. DPDT switch
C. Rotary switch
D. Linear stepper
Answer: C
Clarification: A combinational circuit that selects one from many inputs is known as Multiplexer. A basic multiplexer principle can be demonstrated through the use of a rotary switch. Because rotary switch gives one output corresponding to their inputs.
9. One multiplexer can take the place of ____________
A. Several SSI logic gates
B. Combinational logic circuits
C. Several Ex-NOR gates
D. Several SSI logic gates or combinational logic circuits
Answer: D
Clarification: A combinational circuit that selects one from many inputs is known as Multiplexer. One multiplexer can take the place of several SSI logic gates or combinational logic circuits because it has a lot of functions to perform different operations.
10. The inputs/outputs of an analog multiplexer/demultiplexer are ____________
A. Bidirectional
B. Unidirectional
C. Even parity
D. Binary-coded decimal
Answer: A
Clarification: One multiplexer can be used as demultiplexer. Hence, it is called bidirectional or two-way transmission.
11. If enable input is high then the multiplexer is ______________
A. Enable
B. Disable
C. Saturation
D. High Impedance
Answer: B
Clarification: If enable input is high then the multiplexer is disabled because enable input is in inverted mode always (i.e. E’).
12. What is data routing in a multiplexer?
A. It spreads the information to the control unit
B. It can be used to route data from one of several source to destination
C. It is an application of multiplexer
D. It can be used to route data and it is an application of multiplexer
Answer: D
Clarification: Multiplexing means passing more than one data through the same channel. Data routing is an application of multiplexer and it can be used to route data from one of several source to destination.