### Flip-flop Conversion – SR flip-flop to D flip-flop

Here you would see how to implement a D flip-flop using SR flip-flop step by step - Flip flop Conversion – SR flip-flop to D flip-flop

## Flip-flop Conversion – SR flip-flop to D flip-flop

### Step 1: Write the truth table of the required flip-flop

Here the required flip-flop is D flip-flop.

Hence you need to write the truth table of D flip-flop which is

 D QN QN+1 0 0 0 0 1 0 1 0 1 1 1 1

### Step 2: Write the excitation table of the given flip-flop

In this case the given flip-flop is SR.

Therefore you need to write the excitation table of SR flip-flop which is

 QN QN+1 S R 0 0 0 X 0 1 1 0 1 0 0 1 1 1 X 0

### Step 3: Write the conversion table

The conversion table, which is a combination of truth table and excitation table, to implement D flip-flop using SR flip-flop is as follows

 D QN QN+1 S R 0 0 0 0 X 0 1 0 0 1 1 0 1 1 0 1 1 1 X 0

### Step 4: Find the Boolean expressions for the inputs of the given flip-flop.

In this case the given flip-flop is SR.

Therefore, write the Boolean expressions for S and R from the conversion table using K-Maps.

K-Map for S:

Expression for S would be

S = D

Now, K-Map for R:

Therefore, Expression for R would be

R = D/

### Step 5: Draw the circuit for implementing D flip-flop from SR flip-flop

For this connect the S input of the given flip-flop i.e., SR flip-flop, to D as obtained from the expression of S.

And connect the R input of the SR flip-flop to D/, as obtained from the expression of R.

Therefore, the circuit would be:

In this way a D flip-flop can be implemented using a SR flip-flop. Hope this post on “Flip-flop Conversion – SR flip-flop to D flip-flop” would help in clearing many doubts in flip-flop conversions.