DIGELEC1 (Finals)

Question 1

An example of a basic flip-flop is the

Answer 1

RS flip flop

Question 2

RS flip flop is formed by

Answer 2

two cross-coupled NOR and NAND gate

Question 3

How many outputs and inputs does an RS flip flop have

Answer 3

INPUT
- Reset
- Set

OUTPUT
- Q
- Not Q

Question 4

In RS flip flop the outputs are always

Answer 4

opposite

Question 5

In RS flip flop what input is described as “illegal” or “unallowed”

Answer 5

R = 1
S = 1

Question 6

a device that serves as a temporary buffer memory. It is used to hold data after the input signal is removed.

Answer 6

Latch

Question 7

Example of a latch device

Answer 7

D flip flop

Question 8

The data are latched when the enable line is

Answer 8

Low

Question 9

the output follows the input when the enable line is

Answer 9

High

Question 10

It occurs when the output follows/is the same as the input only when the enable is active

Answer 10

Transparent latch

Question 11

2 categories of binary counters

Answer 11

• Synchronous
• Asynchronous

Question 12

The input clock pulse is first felt by the first flip-flop. The effect is not felt by the second flip-flop immediately because of the delay through the first flip-flop.

Answer 12

Asynchronous

Question 13

Asynchronous counters are commonly referred to as

Answer 13

Ripple counter

Question 14

a counter in which each stage is
clocked at the same time

Answer 14

Synchronous

Question 15

Synchronous counter is also called

Answer 15

Parallel counter

Question 16

have a modulus of ten, or ten states in their counting sequence. A common type of this counter is the BCD (8421) counter, which produces a binary-coded-decimal sequence

Answer 16

Decade counter

Question 17

A counter than can
count in either direction through
a certain sequence.

Answer 17

up-down counter

Question 18

up-down counter is also called

Answer 18

bidirectional counter

Question 19

are constructed of flip-flops wired together.

Answer 19

shift register

Question 20

The circuit whose output at any instant depends only on the input present at that instant only

Answer 20

Combinational circuit

Question 21

The circuit whose output at any instant depends not only on the input present but also on the past output

Answer 21

sequential circuit

Question 22

This type of circuit has no memory unit

Answer 22

Combinational circuit

Question 23

This type of circuit has memory unit for stored past output

Answer 23

sequential circuit

Question 24

An example of this circuit are half adder, full adder, magnitude comparator, multiplexer, demultiplixer

Answer 24

Combinational circuit

Question 25

Example of this circuit are flip flops, register, counter

Answer 25

sequential circuit

Question 26

This type of circuit is faster in speed

Answer 26

Combinational circuit

Question 27

This type of circuit is slower in speed

Answer 27

Sequential circuit

Question 28

2 categories of sequential circuits

Answer 28

- Asynchronous - Synchronous

Question 29

Output changes at discrete interval of time. It is a circuit based on an equal state time or a state time defined by external means such as clock.

Answer 29

Synchronous sequential circuit

Question 30

Output can be changed at any instant of time by changing the input. It is a circuit whose state time depends solely upon the internal logic circuit delays.

Answer 30

Asynchronous sequential circuit

Question 31

A circuit that changes from 1 to 0 or from 0 to 1 when current is applied. It is one bit storage location

Answer 31

basic flip flop

Question 32

SR flip flop is also called

Answer 32

SR latch

Question 33

this circuit is used to overcome invalid state of the SR flip flop

Answer 33

clocked SR flip flop

Question 34

Modification of the clocked SR flip flop

Answer 34

D flip flop

Question 35

refers to a periodic signal where the ON and OFF times do not need to be the same

Answer 35

Clock signal

Question 36

Types of triggering

Answer 36

- Level triggering - Edge triggering

Question 37

The circuit is only activated in whenever the clock pulse happens to be at any particular level

Answer 37

Level triggering

Question 38

Types of level triggering

Answer 38

- Positive - Negative

Question 39

This transition or triggering either occurs from Logic High to Logic Low or from Logic Low to Logic High

Answer 39

Edge triggering

Question 40

Types of edge triggering

Answer 40

- Positive - Negative

Question 41

a device that selects between several analog ordigital input signals and forwards the selected input to a single output line.

Answer 41

multiplexer

Question 42

Multiplexer is also known as

Answer 42

data selector

Question 43

In multiplexer the selection is directed by a separate set of digital inputs known as

Answer 43

select lines

Question 44

It takes a single input signal and routes it to one of many output lines

Answer 44

demultiplexer

Question 45

Demultiplexer is also called as

Answer 45

data distributor

Question 46

is a multiple-input, multiple-output logic circuit that converts coded inputs into coded outputs, where the input and output codes are different.

Answer 46

decoders

Question 47

Types of decoders

Answer 47

- Binary decoders - BCD to 7 segment decoders - Demultiplexers as decoders

Question 48

are devices that convert information from one format or code to another, typically for standardization, speed, secrecy, or compression.

Answer 48

encoder

Question 49

are sensors that detect position and speed by converting rotational mechanical displacements into electrical signals and processing those signals

Answer 49

rotary encoders

Question 50

Types of encoders

Answer 50

- Rotary encoders - Absolute encoders - incremental encoder