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This section includes 190 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Electronics knowledge and support exam preparation. Choose a topic below to get started.
1. |
A MOD-16 ripple counter is holding the count 1001. What will the count be after 31 clock pulses? |
A. | 1000 |
B. | 1010 |
C. | 1011 |
D. | 1101 |
Answer» B. 1010 | |
2. |
After 10 clock cycles, and assuming that the DATA input had returned to 0 following the storage sequence, what values would be stored in 4, 3, 2, 1, 0 of the register in Figure 7-5? |
A. | 0,1,0,1,1 |
B. | 1,1,0,1,0 |
C. | 1,0,1,0,1 |
D. | 0,0,0,0,0 |
Answer» E. | |
3. |
A 5-bit asynchronous binary counter is made up of five flip-flops, each with a 12 ns propagation delay. The total propagation delay (t) is ________. |
A. | 12 ms |
B. | 24 ns |
C. | 48 ns |
D. | 60 ns |
Answer» E. | |
4. |
Any divide-by- counter can be formed by using external gating to ________ at a predetermined number. |
A. | HIGH |
B. | reset |
C. | LOW |
D. | preset |
Answer» C. LOW | |
5. |
The designation means that the ________. |
A. | up count is active-HIGH, the down count is active-LOW |
B. | up count is active-LOW, the down count is active-HIGH |
C. | up and down counts are both active-LOW |
D. | up and down counts are both active-HIGH |
Answer» B. up count is active-LOW, the down count is active-HIGH | |
6. |
What is the maximum delay that can occur if four flip-flops are connected as a ripple counter and each flip-flop has propagation delays of = 22 ns and = 15 ns? |
A. | 15 ns |
B. | 22 ns |
C. | 60 ns |
D. | 88 ns |
Answer» E. | |
7. |
The term refers to events that do not occur at the same time. |
A. | True |
B. | False |
Answer» C. | |
8. |
The term , as applied to counter operations, means that the counter is clocked such that each flip-flop in the counter is triggered at the same time. |
A. | True |
B. | False |
Answer» B. False | |
9. |
A J-K flip-flop excitation table lists the present state, the next state, and the and levels required to produce each transition. |
A. | True |
B. | False |
Answer» B. False | |
10. |
A parallel in/serial out shift register enters all data bits simultaneously and transfers them out one bit at a time. |
A. | True |
B. | False |
Answer» B. False | |
11. |
Another term used to describe up/down counters is . |
A. | True |
B. | False |
Answer» B. False | |
12. |
When a flip-flop is used in a circuit, we only have to consider the level at and at the active clock edge to know the states of the outputs. |
A. | True |
B. | False |
Answer» C. | |
13. |
Cascade means to connect the output of one flip-flop to the clock input of the next. |
A. | True |
B. | False |
Answer» B. False | |
14. |
The duty cycle of the most significant bit from a 4-bit (0–9) BCD counter is ________. |
A. | 10% |
B. | 20% |
C. | 50% |
D. | 80% |
Answer» C. 50% | |
15. |
List the state of each output pin of a 7447 if RBI = 0, LT = 1, A0 = 1, A1 = 0, A2 = 0, and A3 = 1. |
A. | RBO = 0, a = 0, b = 0, c = 0, d = 1, e = 1, f = 0, g = 0 |
B. | RBO = 1, a = 0, b = 0, c = 0, d = 1, e = 1, f = 0, g = 0 |
C. | RBO = 0, a = 0, b = 0, c = 0, d = 0, e = 1, f = 0, g = 0 |
D. | RBO = 1, a = 0, b = 0, c = 0, d = 0, e = 1, f = 0, g = 0 |
Answer» B. RBO = 1, a = 0, b = 0, c = 0, d = 1, e = 1, f = 0, g = 0 | |
16. |
The parallel outputs of a counter circuit represent the _____________ |
A. | Parallel data word |
B. | Clock frequency |
C. | Counter modulus |
D. | Clock count |
Answer» E. | |
17. |
BCD counter is also known as ____________ |
A. | Parallel counter |
B. | Decade counter |
C. | Synchronous counter |
D. | VLSI counter |
Answer» C. Synchronous counter | |
18. |
Three decade counter would have ____________ |
A. | 2 BCD counters |
B. | 3 BCD counters |
C. | 4 BCD counters |
D. | 5 BCD counters |
Answer» C. 4 BCD counters | |
19. |
Synchronous counter is a type of ____________ |
A. | SSI counters |
B. | LSI counters |
C. | MSI counters |
D. | VLSI counters |
Answer» D. VLSI counters | |
20. |
Ripple counters are also called ____________ |
A. | SSI counters |
B. | Asynchronous counters |
C. | Synchronous counters |
D. | VLSI counters |
Answer» C. Synchronous counters | |
21. |
A decimal counter has ______ states. |
A. | 5 |
B. | 10 |
C. | 15 |
D. | 20 |
Answer» C. 15 | |
22. |
What is the maximum possible range of bit-count specifically in n-bit binary counter consisting of ‘n’ number of flip-flops? |
A. | 0 to 2n |
B. | 0 to 2n + 1 |
C. | 0 to 2n – 1 |
D. | 0 to 2n+1/2 |
Answer» D. 0 to 2n+1/2 | |
23. |
A counter circuit is usually constructed of ____________ |
A. | A number of latches connected in cascade form |
B. | A number of NAND gates connected in cascade form |
C. | A number of flip-flops connected in cascade |
D. | A number of NOR gates connected in cascade form |
Answer» D. A number of NOR gates connected in cascade form | |
24. |
In digital logic, a counter is a device which ____________ |
A. | Counts the number of outputs |
B. | Stores the number of times a particular event or process has occurred |
C. | Stores the number of times a clock pulse rises and falls |
D. | Counts the number of inputs |
Answer» C. Stores the number of times a clock pulse rises and falls | |
25. |
What decimal value is required to produce an output at "X" ? |
A. | 1 |
B. | 1 or 4 |
C. | 2 |
D. | 5 |
Answer» E. | |
26. |
Parallel in/parallel out registers have parallel input and output busses. |
A. | 1 |
B. | |
Answer» B. | |
27. |
Basic counters can be cascaded in parallel to increase the number of data bits that the counter can handle. |
A. | 1 |
B. | |
Answer» C. | |
28. |
All decade counters are BCD counters. |
A. | 1 |
B. | |
Answer» C. | |
29. |
Referring to the function table given below, taking the CLEAR, S1, and S0 inputs all HIGH ________. |
A. | will inhibit the operation of the register |
B. | will reset the parallel registers and inhibit the serial data inputs |
C. | will cause the parallel data inputs to be loaded and passed to the parallel data outputs |
D. | will depend on what values are loaded into the parallel data inputs |
Answer» D. will depend on what values are loaded into the parallel data inputs | |
30. |
In a seven-segment LED display, the BCD must be decoded into a format that can be used to drive the decimal numeric display. |
A. | 1 |
B. | |
Answer» B. | |
31. |
A parallel in/serial out shift register enters all data bits simultaneously and transfers them out one bit at a time. |
A. | 1 |
B. | |
Answer» B. | |
32. |
A J-K flip-flop excitation table lists the present state, the next state, and the J and K levels required to produce each transition. |
A. | 1 |
B. | |
Answer» B. | |
33. |
The duty cycle of the most significant bit from a 4-bit (0–9) BCD counter is ________. |
A. | 0.1 |
B. | 0.2 |
C. | 0.5 |
D. | 0.8 |
Answer» C. 0.5 | |
34. |
The terminal count of a typical modulus-10 binary counter is 1010. |
A. | 1 |
B. | |
Answer» C. | |
35. |
Once an up/down counter begins its count sequence, it cannot be reversed. |
A. | 1 |
B. | |
Answer» C. | |
36. |
The ________ counter in the Altera library has controls that allow it to count up or down, and perform synchronous parallel load and asynchronous cascading. |
A. | 74134 |
B. | LPM |
C. | synchronous |
D. | AHDL |
Answer» C. synchronous | |
37. |
Synchronous binary counters can only be used for the application of timing of digital systems. |
A. | 1 |
B. | |
Answer» C. | |
38. |
The decimal equivalent of the largest number that can be stored in a 4-bit binary counter is ________. |
A. | 8 |
B. | 15 |
C. | 16 |
D. | 32 |
Answer» C. 16 | |
39. |
An asynchronous counter differs from a synchronous counter in the method of clocking. |
A. | 1 |
B. | |
Answer» B. | |
40. |
Shift register counters use logic functions to reset the registers when the desired count is reached. |
A. | 1 |
B. | |
Answer» C. | |
41. |
Most sequential circuits contain a combinational logic section and a memory section. |
A. | 1 |
B. | |
Answer» B. | |
42. |
________ is the output frequency of the counter shown below. |
A. | 4 MHz |
B. | 20 kHz |
C. | 210.5 kHz |
D. | 800 Hz |
Answer» C. 210.5 kHz | |
43. |
The given circuit represents a(n) ________. |
A. | four-bit binary counter |
B. | asynchronous BCD decade counter |
C. | synchronous BCD decade counter |
D. | BCD-to-decimal decoder |
Answer» D. BCD-to-decimal decoder | |
44. |
When implementing a complete system application using IC counter chips, output devices such as LED indicators must be configured to operate from the counter outputs. |
A. | 1 |
B. | |
Answer» C. | |
45. |
Shift registers are used to store and transfer data. |
A. | 1 |
B. | |
Answer» B. | |
46. |
Generally speaking, the synchronous counter requires more circuitry than an asynchronous counter. |
A. | 1 |
B. | |
Answer» B. | |
47. |
Assume you want to determine the timing diagram for a 4-bit counter using an oscilloscope. The best choice for an oscilloscope trigger signal is ________. |
A. | the most significant bit (MSB) |
B. | the least significant bit (LSB) |
C. | the clock signal |
D. | from a composite of the MSB and LSB |
Answer» D. from a composite of the MSB and LSB | |
48. |
The term synchronous, as applied to counter operations, means that the counter is clocked such that each flip-flop in the counter is triggered at the same time. |
A. | 1 |
B. | |
Answer» B. | |
49. |
A 4-bit binary up counter has an input clock frequency of 20 kHz. The frequency of the most significant bit is ________. |
A. | 1.25 kHz |
B. | 2.50 kHz |
C. | 160 kHz |
D. | 320 kHz |
Answer» B. 2.50 kHz | |
50. |
Asynchronous counters are known as modulus counters. |
A. | 1 |
B. | |
Answer» C. | |