Signals and Switches in Digital Logic Design MCQs

Signals and Switches in Digital Logic Design MCQs

 Q1. Why does the TTL family use a totem-pole circuit on the output?. 

A. It provides active pull-up.. 

B. It provides active pull-down.. 

C. It provides active pull-up and active pull-down.. 

D. None of the mentioned. 

Answer= It provides active pull-up and active pull-down.

Q2. What is the freQncy of a clock waveform if the period of that waveform is 1.25 micro-sec?. 

A. 8 kHz. 

B. 0.8 kHz. 

C. 0.8 MHz. 

D. 8 MHz. 

Answer= 0.8 MHz

Q3. Internally, a computer's binary data are almost always transmitted on parallel channels, commonly referred to as the:. 

A. parallel bus. 

B. serial bus. 

C. data bus. 

D. memory bus. 

Answer= data bus

Q4. Why is parallel data transmission preferred over serial data transmission for most applications?. 

A. It is much slower.. 

B. It is cheaper.. 

C. More people use it.. 

D. It is much faster.. 

Answer= It is much faster.

Q5. With surface-mount technology (SMT), the devices should:. 

A. utilize transistor outline connections. 

B. mount directly. 

C. have parallel connecting pins. 

D. require holes and pads. 

Answer= mount directly

Q6. To forward bias a diode, a ________ potential is needed on the ________ and a ________ is needed on the ________.. 

A. negative, cathode, positive, anode. 

B. negative, anode, positive, cathode. 

C. Both (A) and (B). 

D. Neither (A) nor (B). 

Answer= negative, cathode, positive, anode

Q7. Why, in most applications, are transistor switches used in place of relays?. 

A. They consume less power.. 

B. They are faster.. 

C. They are quieter and smaller.. 

D. all of the above. 

Answer= all of the above

Q8. The family of logic that is composed of bipolar junction transistors is ____.. 

A. TTL. 


C. DIP. 

D. BJT. 

Answer= TTL

Q9. What can a relay provide between the triggering source and the output that semiconductor switching devices cannot?. 

A. total isolation. 

B. faster. 

C. higher current rating. 

D. total isolation and higher current rating. 

Answer= total isolation and higher current rating

Q10. The serial format for transmitting binary information uses:. 

A. a single conductor. 

B. multiple conductors. 

C. infrared technology. 

D. fiber-optic. 

Answer= a single conductor

Q11. Which device(s) have almost ideal ON and OFF resistances?. 

A. electromechanical relays. 

B. manual switches. 

C. semiconductor devices (diodes and transistors). 

D. electromechanical relays and manual switches. 

Answer= electromechanical relays and manual switches

Q12. A diode placed in parallel across a relay coil serves what function?. 

A. to regulate input voltage. 

B. to protect the coil from arcing. 

C. to ensure most of the current passes through the coil. 

D. to reduce arcing across the relay contacts. 

Answer= to protect the coil from arcing

Q13. Serial communication can be sped up by:. 

A. using silver or gold conductors instead of copper. 

B. using high-speed clock signals. 

C. adjusting the duty cycle of the binary information. 

D. using silver or gold conductors instead of copper and high-speed clock signals. 

Answer= using high-speed clock signals

Q14. An indication of cutoff in an NPN bipolar transistor is that the:. 

A. collector current is maximum. 

B. collector-to-emitter voltage equals zero. 

C. base-to-emitter voltage equals 0.7 V. 

D. collector to emitter appears to be open. 

Answer= collector to emitter appears to be open

Q15. When an IC has two rows of parallel connecting pins, the device is referred to as a:. 

A. QFP. 

B. DIP. 



Answer= DIP

Q16. Normal operation of an NPN bipolar transistor requires the base to be ________ with respect to the emitter, and ________ with respect to the collector.. 

A. positive, negative. 

B. positive, positive. 

C. negative, positive. 

D. negative, negative. 

Answer= positive, negative

Q17. What is the minimum voltage required before a diode will allow current to flow between the cathode and the anode?. 

A. 0.7 V. 

B. 0.07 V. 

C. 4.3 V. 

D. 0.2 V. 

Answer= 0.7 V

Q18. What is the advantage of using serial data transmission over parallel data transmission?. 

A. It is slower.. 

B. Only one pair of wires is required.. 

C. More people use it.. 

D. It is faster.. 

Answer= Only one pair of wires is required.

Q19. A TTL totem-pole circuit is designed so that the output transistors:. 

A. are always on together. 

B. provide phase splitting. 

C. provide voltage regulation. 

D. are never on together. 

Answer= are never on together

Q20. What is the advantage of using CMOS logic over TTL?. 

A. It switches faster.. 

B. It uses less power.. 

C. It is larger.. 

D. cost. 

Answer= It uses less power.

Q21. What is used to graphically show the time relationship between two or more digital waveforms?. 

A. reference diagram. 

B. timing diagram. 

C. voltage curve. 

D. load line. 

Answer= timing diagram

Q22. What is a disadvantage of CMOS in place of TTL?. 

A. It switches slower.. 

B. It uses less power.. 

C. It is smaller.. 

D. cost. 

Answer= It switches slower.

Q23. The units for the HIGH time for a periodic wave are ________.. 

A. seconds. 

B. hertz. 

C. cycles. 

D. %. 

Answer= seconds

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