MCQOPTIONS
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MCQOPTIONS
This section includes 64 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
What is the standard TTL noise margin? |
| A. | 5.0 V |
| B. | 0.0 V |
| C. | 0.8 V |
| D. | 0.4 V |
| Answer» E. | |
| 52. |
Why must CMOS devices be handled with care? |
| A. | so they don’t get dirty |
| B. | because they break easily |
| C. | because they can be damaged by static electricity discharge |
| Answer» D. | |
| 53. |
Which of the following summarizes the important features of emitter-coupled logic (ECL)? |
| A. | low noise margin, low output voltage swing, negative voltage operation, fast, and high power consumption |
| B. | good noise immunity, negative logic, high-frequency capability, low power dissipation, and short propagation time |
| C. | low propagation time, high-frequency response, low power consumption, and high output voltage swings |
| D. | poor noise immunity, positive supply voltage operation, good low-frequency operation, and low power |
| Answer» B. good noise immunity, negative logic, high-frequency capability, low power dissipation, and short propagation time | |
| 54. |
What should be done to unused inputs on TTL gates? |
| A. | They should be left disconnected so as not to produce a load on any of the other circuits and to minimize power loading on the voltage source. |
| B. | All unused gates should be connected together and tied to V< sub=""> through a 1 k resistor.<> |
| C. | All unused inputs should be connected to an unused output; this will ensure compatible loading on both the unused inputs and unused outputs. |
| D. | Unused AND and NAND inputs should be tied to VCC through a 1 k resistor; unused OR and NOR inputs should be grounded. |
| Answer» E. | |
| 55. |
Which family of devices has the characteristic of preventing saturation during operation? |
| A. | TTL |
| B. | MOS |
| C. | ECL |
| D. | IIL |
| Answer» D. IIL | |
| 56. |
Which of the following logic families has the shortest propagation delay? |
| A. | CMOS |
| B. | BiCMOS |
| C. | ECL |
| D. | 74SXX |
| Answer» D. 74SXX | |
| 57. |
Special handling precautions should be taken when working with MOS devices. Which of the following statements is not one of these precautions? |
| A. | All test equipment should be grounded. |
| B. | MOS devices should have their leads shorted together for shipment and storage. |
| C. | Never remove or insert MOS devices with the power on. |
| D. | Workers handling MOS devices should not have grounding straps attached to their wrists. |
| Answer» E. | |
| 58. |
How does the 4000 series of CMOS logic compare in terms of speed and power dissipation to the standard family of TTL logic? |
| A. | more power dissipation and slower speed |
| B. | more power dissipation and faster speed |
| C. | less power dissipation and faster speed |
| D. | less power dissipation and slower speed |
| Answer» E. | |
| 59. |
What is the difference between the 54XX and 74XX series of TTL logic gates? |
| A. | 54XX is faster. |
| B. | 54XX is slower. |
| C. | 54XX has a wider power supply and expanded temperature range. |
| D. | 54XX has a narrower power supply and contracted temperature range. |
| Answer» D. 54XX has a narrower power supply and contracted temperature range. | |
| 60. |
In ECL, the HIGH and LOW levels are determined by which transistor in a differential amplifier is conducting more. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 61. |
What is the advantage of using low-power Schottky (LS) over standard TTL logic? |
| A. | more power dissipation |
| B. | less power dissipation |
| C. | cost is less |
| D. | cost is more |
| Answer» C. cost is less | |
| 62. |
Assume that a particular IC has a supply voltage (Vcc) equal to +5 V and ICCH = 10 mA and ICCL = 23 mA. What is the power dissipation for the chip? |
| A. | 50 mW |
| B. | 82.5 mW |
| C. | 115 mW |
| D. | 165 mW |
| Answer» C. 115 mW | |
| 63. |
Totem-pole outputs ________ be connected ________ because ________. |
| A. | can, in parallel, sometimes higher current is required |
| B. | cannot, together, if the outputs are in opposite states excessively high currents can damage one or both devices |
| C. | should, in series, certain applications may require higher output voltage |
| D. | can, together, together they can handle larger load currents and higher output voltages |
| Answer» C. should, in series, certain applications may require higher output voltage | |
| 64. |
What is unique about TTL devices such as the 74SXX? |
| A. | These devices use Schottky transistors and diodes to prevent them from going into saturation; this results in faster turn-on and turn-off times, which translates into higher frequency operation. |
| B. | The gate transistors are silicon (S), and the gates therefore have lower values of leakage current. |
| C. | The S denotes the fact that a single gate is present in the IC rather than the usual package of 2–6 gates. |
| D. | The S denotes a slow version of the device, which is a consequence of its higher power rating. |
| Answer» B. The gate transistors are silicon (S), and the gates therefore have lower values of leakage current. | |