SR Flip Flop to JK Flip Flop Conversion

Summary

This educational video script guides through the conversion of an SR flip-flop to a JK flip-flop, a crucial topic for exams. It outlines a five-step process: identifying available and required flip-flops, creating a characteristic table for the JK flip-flop, determining the excitation table for the SR flip-flop, deriving S and R values using a K-map, and implementing the changes with AND gates. The script emphasizes the importance of following each step accurately to avoid mistakes and achieve the correct conversion.

Takeaways

• 📘 The video script is about converting an SR flip-flop to a JK flip-flop using a five-step process.
• 🔍 Step one emphasizes the importance of correctly identifying the available (SR) and required (JK) flip-flops to avoid confusion.
• 📊 In step two, the characteristic table for the JK flip-flop is created, which is essential for determining the next state of the flip-flop.
• 🔄 The characteristic table shows the next state (q n+1) based on the current state (q) and the inputs J and K.
• 📝 Step three involves creating an excitation table for the available SR flip-flop, which helps in understanding the inputs required for the desired state changes.
• 🗂 The excitation table for the SR flip-flop is simplified to only four combinations instead of eight, making it easier to fill and understand.
• 🔑 Step four uses a K-map to determine the Boolean expressions for S and R inputs of the SR flip-flop based on the JK flip-flop's characteristic table.
• 🔍 The K-map simplifies the process of finding the expressions for S and R by grouping 1s and avoiding the involvement of 'don't care' conditions.
• 🔧 The final step is the implementation of the derived Boolean expressions to modify the SR flip-flop into a JK flip-flop using AND gates.
• 🛠️ The implementation involves connecting the outputs of the SR flip-flop (q and q') with the inputs J and K through AND gates to achieve the desired functionality.
• 📚 The script concludes by highlighting the importance of following all five steps to correctly convert an SR flip-flop to a JK flip-flop.

Q & A

What is the main topic of the video script?

The main topic of the video script is the conversion of an SR flip-flop to a JK flip-flop using a five-step process.

Why is it important to determine the available and required flip-flops correctly?

It is important to determine the available and required flip-flops correctly because if they are switched, the entire conversion process will be reversed, leading to an incorrect answer.

What is a characteristic table and why is it needed for the JK flip-flop?

A characteristic table is a table that defines the next state of a flip-flop based on its current state and input conditions. It is needed for the JK flip-flop to understand the behavior of the flip-flop in different input scenarios.

What are the four possible combinations for the excitation table of an SR flip-flop?

The four possible combinations for the excitation table of an SR flip-flop are when both S and R are 0, when S is 0 and R is 1, when S is 1 and R is 0, and when both S and R are 1.

What does 'q n plus 1' represent in the context of flip-flops?

'q n plus 1' represents the next state of the flip-flop, which is the state it will transition to based on the current state and input conditions.

How is the excitation table for an SR flip-flop constructed?

The excitation table for an SR flip-flop is constructed by listing all possible combinations of the current state (q) and the next state (q n plus 1), and then determining the inputs S and R that would result in those transitions.

What is the purpose of a K-map in the conversion process?

The purpose of a K-map (Karnaugh map) in the conversion process is to simplify and minimize the Boolean expressions for the S and R inputs of the SR flip-flop, making it easier to determine the equivalent JK flip-flop inputs.

What are the Boolean expressions for S and R obtained from the K-map?

The Boolean expressions for S and R obtained from the K-map are S = Q'J and R = QnK, where Q' is the complement of Q, and n represents the current state.

How can an SR flip-flop be converted to a JK flip-flop using logic gates?

An SR flip-flop can be converted to a JK flip-flop by using two AND gates. The inputs to these gates are determined by the Boolean expressions for S and R, and the outputs of the gates are used to replace the S and R inputs of the original SR flip-flop.

What is the significance of the five-step process in converting an SR flip-flop to a JK flip-flop?

The five-step process is significant as it provides a structured and systematic approach to converting an SR flip-flop to a JK flip-flop, ensuring that all necessary considerations are accounted for and reducing the likelihood of errors.

Outlines

00:00

🔄 Converting SR Flip Flop to JK Flip Flop

This paragraph introduces a technical tutorial on converting an SR flip flop to a JK flip flop, a common topic in digital electronics. It outlines a five-step process to perform the conversion, emphasizing the importance of correctly identifying the available and required flip flops to avoid errors. The paragraph also covers the creation of a characteristic table for the JK flip flop, explaining the different states and outputs based on the inputs J and K. The explanation includes the memory state, where the output remains the same, and the toggle state, where the output changes based on the input conditions.

05:03

📋 Excitement Table and Boolean Expressions for Conversion

The second paragraph delves into the next steps of the conversion process. It discusses the creation of an excitation table for the SR flip flop, detailing the possible combinations of inputs and outputs. The paragraph then moves on to the use of a K-map to determine the Boolean expressions for S and R, which are crucial for the conversion. The K-map is used to simplify and group the expressions, resulting in S being equal to the complement of Q and J, and R being equal to Q and K. The final part of the paragraph describes the implementation of these expressions using AND gates to modify the existing SR flip flop into a JK flip flop, concluding the conversion process.

Keywords

💡Flip Flop

A flip flop in digital electronics is a circuit that has two stable states and can be used as a memory element. It is fundamental to the operation of computers and other digital systems. In the video, the focus is on converting an SR (Set-Reset) flip flop to a JK flip flop, which is a type of flip flop with different inputs and behavior.

💡SR Flip Flop

The SR flip flop, also known as the Set-Reset flip flop, is a type of flip flop with two inputs: Set (S) and Reset (R). When S is high, it sets the output to high regardless of the reset input, and when R is high, it resets the output to low. The video script discusses converting this type of flip flop to a JK flip flop.

💡JK Flip Flop

The JK flip flop is a type of flip flop with two inputs, J and K, that can be used to set, reset, toggle, or maintain the current state of the flip flop. It is more versatile than the SR flip flop and is the target of the conversion process described in the video.

💡Characteristic Table

A characteristic table is used to define the behavior of a flip flop based on its inputs and current state. In the video, the characteristic table for the JK flip flop is created to understand the different combinations of J and K inputs and their effects on the output state.

💡Memory State

In the context of flip flops, the memory state refers to the ability of the flip flop to retain its output state as the input conditions change. The video mentions the memory state when explaining the behavior of the JK flip flop when both J and K are set to 0.

💡Excitation Table

An excitation table is used to determine the next state of a flip flop based on its current state and inputs. For the SR flip flop, the excitation table is discussed in the video to show how the S and R inputs affect the flip flop's state.

💡Karnaugh Map (K-Map)

A Karnaugh map is a graphical method used to simplify Boolean algebra expressions. In the video, K-maps are used to determine the Boolean expressions for the S and R inputs of the SR flip flop that will result in the behavior of a JK flip flop.

💡Boolean Expression

A Boolean expression is a mathematical expression that can take on values of true or false, represented by 1 and 0 in digital electronics. The video script provides the Boolean expressions for S and R that are derived from the K-maps to convert the SR flip flop to a JK flip flop.

💡AND Gate

An AND gate is a digital logic gate that outputs high only if all of its inputs are high. In the video, AND gates are used in the final implementation step to create the S and R inputs for the converted JK flip flop.

💡Negative Edge Triggered

Negative edge triggered refers to a type of flip flop that changes state on the falling edge (from high to low) of the clock signal. The video mentions this term when discussing the implementation of the converted JK flip flop.

Highlights

Introduction to converting SR flip-flop to JK flip-flop, a crucial topic for exams.

Emphasis on correctly identifying available (SR) and required (JK) flip-flops to avoid incorrect conversions.

Explanation of the importance of the characteristic table for the JK flip-flop.

Characteristic table completion for JK flip-flop with different J and K combinations.

Memory state and toggle state explanations for JK flip-flop behavior.

Transition to Step 3: Determining the excitation table for the available SR flip-flop.

Description of the excitation table construction for SR flip-flop.

Importance of matching inputs for S and R to fill the excitation table correctly.

Step 4 involves determining S and R values using a K-map.

Guidance on creating a K-map for S and R with inputs q(n), J, and K.

Simplification of K-map groups for S and R to derive Boolean expressions.

Boolean expression derivation for S as Q' (complement of Q) and for R as Q and K.

Implementation of the derived expressions to convert SR to JK flip-flop using AND gates.

Detailed walk-through of the changes needed in the SR flip-flop circuit to achieve JK functionality.

Use of AND gates to combine Q, Q', J, and K for the conversion process.

Final step of implementing the conversion with a visual representation of the modified circuit.

Conclusion emphasizing the five-step process for accurate SR to JK flip-flop conversion.

Transcripts

foreign

let's do one more problem in our flip

flop conversion and this time we are

going to convert Sr flip flop to JK flip

flop we are having our five step to

convert the SR to JK a very important

question to be asked in your exam the SR

flip flop to jkl flip flop conversion so

let's move towards step number one in

Step number one we have to determine the

available flip flop and the required

flip flop so let me write it down first

the available flip flop the required

flip flop it is very important to

determine them correctly because if you

switch them everything is going to be

reversed and your answer will be wrong

so available flip flop is our Sr flip

flop and the required flip flop is my JK

flip flop now you already know in Step

number two we have to find out the

characteristic table for your required

flip flop and required flip flop is JK

so we will make a characteristic table

for JK flip flop I have already made the

table so let me paste it down and this

is my table in this we have to find out

the value of q n plus 1 to complete the

characteristic table so let's do it when

J is 0 K is 0 we know that it is the

memory State your output or your state

is going to be the same as the previous

one so previous one was 0 so q n plus 1

will also be 0 When J is 0 K is 1 q n

plus 1 is 0 When J is 1 K is 0 q n plus

1 is 1 when both of them J and K are 1

it means it is the toggle State and q n

plus 1 is going to be q and complement

so q n was 0 and taking its complement I

am having one when J is 0 K 0 again

memory so 1 in this case 0 1 and again

toggle state so q n plus 1 is 0. the

complement of 1 is now zero so we are

done with our step number two in which

we have found out the characteristic

table for our required flip flop up now

we have to move towards step number

three in Step number three we have to

determine the excitation table for the

available flip flop and the available

flip flop is my Sr so let's make the

excitation table for the SR flip flop

before that let me write down the

excitation table here as

an R are the two outputs and the inputs

are q n q n plus 1

so four possible combinations let me

write it down quickly you can also refer

to your notes

0 1 0 don't care don't care zero one

zero every time it is good to make the

excitation table here especially for the

SR flip flop and JK flip flop because in

that case we are having eight

combinations so that we can easily fill

the table it helps and it avoids

mistakes so I'm having S and R here we

have to match this two columns

because that is what we need to get our

excitation table the two inputs so let's

do it

when both of them are 0 it means the

first case s is 0 R is don't here again

both of them are zero so zero don't care

0 1 0 1 gives us 1 0 1 0 again 1 0 1 1

gives us don't care zero so don't care 0

1 0 1 0 gives us 0 1 so 0 1 1 don't care

zero one zero zero one so you can see

once I have made this table here it's

very easy to fill the values for S and R

so it's a good practice to do now we are

done with our three steps the fourth

step is to determine the value of S and

R by using the K map so let's make a h

cell K map for S and the same K map for

r

so you can pause the video and determine

the value by yourself

the inputs are q n j k

0 1 0 0 0 1 1 1 1 1 0 and I will copy

this

and paste it down so that we can use it

for R also

so this is for r

this is for S this is for R okay let's

do it

s is 0 0 1 1 so 0 0 1 1 don't care zero

don't care zero so don't care zero don't

care zero

similarly R is don't here don't care

zero zero

zero one zero one so I have filled the

map now let's make the groups let's do

it for S we are having two ones here and

it's easy to combine them simply like

this no need to involve any don't here

and again in this case also we can

combine the two one simply like this

it's a very simple K Map to solve so s

is equal to q and complement

and in this if I see J is 1 K is

changing from 1 to 0 so I am having J

and R is equal to q n

and here I am having K because J is

changing from 0 to 1 so q and K

so this is the Boolean expression for

our S and R now the last and the final

step is to implement them and you

already know I'm having s r flip flop

already so I will make Sr flip flop

this is my Sr flip flop and I will do

the changes that we have got in this

step 4

to make it JK

this is output qn

q n complement and our clock goes here

okay this symbol represents that it is

Negative Edge triggered okay and now we

have to see the value for s from the

step number four it is q and complement

J let me do it in different colors so

that we can see what are the changes

that we have to do so q and complement I

will take from here

and it is the end combination of Q and

complement and J so I will use a and

gate here

okay

and the one of the input to this and

gate is J and the other input is of

course q n complement that we have taken

out

so we are done with our s we have to do

this changes now we will see for r r is

q n and K so I will take q n from here

like this and use another and gate

the one input to the and gate is of

course K and the other input is q n so

in this way we can convert our Sr flip

flop to JK flip flop by just using two

and Gates and taking the outputs q n and

q and complement and using it as the

expression given here so this was a very

important presentations and you have to

follow all these five steps to get your

answer correct so this is all now see

you in the next presentation