Home Topics Quiz Login

Signals and Switches MCQ Questions & Answers

Signals and Switches MCQs : This section focuses on the "Signals and Switches". These Multiple Choice Questions (MCQs) should be practiced to improve the Signals and Switches skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

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

View Answer

Question 2

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

View Answer

Question 3

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

View Answer

Question 4

How long will it take to serially transmit the hexadecimal number C316 if the clock frequency is 1.5 MHz?

A. 4.69 ms
B. 4.69 s
C. 5.33 ms
D. 5.33 s

View Answer

Question 5

In a graphical representation of voltage versus time, ________ is displayed on the ________ axis and ________ is displayed on the ________ axis.

A. time, y, voltage, x
B. voltage, y, time, x

View Answer

Question 6

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

View Answer

Question 7

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

View Answer

Question 8

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

View Answer

Question 9

The abbreviation NO, when used with respect to electromechanical relays, stands for not operational.


View Answer

Question 10

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


View Answer

Question 11

The hexadecimal number 4B16 is transmitted as an 8-bit word in parallel. What is the time required for this transmission if the clock frequency is 2.25 MHz?

A. 444 ns
B. 444 s
C. 3.55 s
D. 3.55 ms

View Answer

Question 12

The period of a waveform is the percentage of time the signal is HIGH.


View Answer

Question 13

The serial format for transmitting binary information uses:

A. a single conductor
B. multiple conductors
C. infrared technology
D. fiber-optic

View Answer

Question 14

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

A. seconds
B. hertz
C. cycles
D. %

View Answer

Question 15

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

View Answer

Question 16

TTL logic chips must have connections to Vcc and ground, even if all inputs and outputs are properly used and tied to valid signals.


View Answer

Question 17

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

View Answer

Question 18

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

View Answer

Question 19

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

View Answer

Question 20

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.

View Answer

Question 21

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

View Answer

Question 22

What is the period of a clock waveform that has a frequency of 15.4 kHz?

A. 649 s
B. 6.49 s
C. 64.9 s
D. 0.649 s

View Answer

Question 23

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

View Answer

Question 24

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


View Answer

Question 25

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

View Answer

Question 26

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.

View Answer

Question 27

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.

View Answer

Question 28

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

View Answer

Question 29

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

View Answer