Flip-Flops

Question 1

What are the two main categories of bistable devices ?

Answer 1

Latch and Flip-Flop

Question 2

How many stable states do bistable devices have ?

Answer 2

Two

Question 3

What are the two stable states of a bistable device ?

Answer 3

SET and RESET

Question 4

How long can a bistable device retain a state ?

Answer 4

Indefinitely

Question 5

How does this help ?

Answer 5

It works as a storage device

Question 6

What are some devices which use bistability, apart from latches and flip flops ?

Answer 6

Relaxation oscillators, Multivibrators and Schmitt Triggers

Question 7

How many states do flip flops and latches have ?

Answer 7

Two (They are bistable devices)

Question 8

What is the basic difference in between a latch and a flip flop ?

Answer 8

It is the way in which they change from one state to another

Question 9

What are flip flops the building block of ?

Answer 9

Counters and registers

Question 10

How many stable states does a monostable multivibrator have ?

Answer 10

Only one

Question 11

What does a monostable multivibrator do when triggered ?

Answer 11

Produces a controlled width pulse

Question 12

How many controlled width pulses does a monostable multivibrator produce when triggered ?

Answer 12

One

Question 13

How many stable states does an astable multivibrator have ?

Answer 13

None.

Question 14

What is an astable multivibrator used for ?

Answer 14

Oscillators primarily

Question 15

What are used as sources for timing waveforms in digital waveforms ?

Answer 15

Pulse oscillators

Question 16

Are flip flops synchronous or asynchronous ?

Answer 16

Synchronous

Question 17

Why are flip flops called synchronous bistable devices ?

Answer 17

The output changes in synchronisation with clock (CLK)

Question 18

When does an edge triggered flip flop change state ?

Answer 18

Either at positive(rising) or negative(falling) edge

Question 19

What does a positive edge mean ?

Answer 19

The clock signal rises at that point

Question 20

What is the triangle used to represent clock signals in block diagrams known as ?

Answer 20

Dynamic input indicator

Question 21

Why is a D flip flop synchronous ?

Answer 21

The input is transferred to output only on the triggering edge

Question 22

What type of RAM uses flip flops ?

Answer 22

SRAM (Static Random Access Memory)

Question 23

Why is SRAM called volatile memory ?

Answer 23

It retains memory as long as DC power is applied

Question 24

What is an alternative to SRAM ?

Answer 24

DRAM (Dynamic RAM)

Question 25

What is the basic storage element of DRAM ?

Answer 25

Capacitance, not flip flops

Question 26

How should data be maintained in the DRAM ?

Answer 26

It must be periodically refreshed.

Question 27

What is a T-Flip Flop, as a version of JK flip flop ?

Answer 27

A JK Flip flop connected for toggle operation

Question 28

What is the propagation time delay ?

Answer 28

Time in between input being applied and output having changed

Question 29

Name three applications of flip flops

Answer 29

Data Storage
Frequency Division
Counter Applications

Question 30

What is frequency division ?

Answer 30

Reduction of the frequency of a periodic waveform

Question 31

What is the output of a pulse waveform, applied to a clock signal of a D or JK Flip flop ?

Answer 31

A square wave with one half the the frequency of the clock input

Question 32

How much does a flip flop reduce the frequency of a waveform by ?

Answer 32

Reduces it by half

Question 33

What happens when this output of a flip flop is fed as an input to another flip flop ?

Answer 33

Frequency reduces by one-fourth.

Question 34

What happens when N flip flops are connected together ?

Answer 34

Frequency is divided by 2^N