S-R Flip-Flop:
The S-R (Set-Reset) flip-flop is a basic building block of digital circuits. It has two stable states, Q=1 and Q=0, and can be used to store one bit of information. The flip-flop has two inputs, S (Set) and R (Reset), and two outputs, Q and Q'.

D Flip-Flop:
The D (Data) flip-flop is another type of flip-flop that can store one bit of information. It has a single data input, D, and two outputs, Q and Q'. The flip-flop changes its output based on the data input when a clock signal is applied.

Conversion from S-R to D Flip-Flop:
To convert an S-R flip-flop into a D flip-flop, we can use an inverter (NOT gate) to connect the S and R inputs. The inverter is used to complement the S input and connect it to the R input. This creates a D input for the D flip-flop.

Explanation:
When the S and R inputs of an S-R flip-flop are both 0, the flip-flop maintains its previous state. When both inputs are 1, the flip-flop enters an invalid state where both Q and Q' are 1. This situation is known as the "forbidden state" and should be avoided.

To convert the S-R flip-flop to a D flip-flop, we can connect the S and R inputs through an inverter. This means that when the D input is 0, the S and R inputs of the S-R flip-flop will be 1, forcing it into the forbidden state. When the D input is 1, the S and R inputs will be 0, allowing the flip-flop to maintain its previous state or change it based on the clock signal.

Benefits of using an Inverter:
- The use of an inverter ensures that the S and R inputs of the S-R flip-flop are always complementary to each other, avoiding the forbidden state.
- The inverter also simplifies the circuitry required for the conversion, as it only requires a single gate.

Conclusion:
By connecting the S and R inputs of an S-R flip-flop through an inverter, we can convert it into a D flip-flop. This conversion allows the flip-flop to store one bit of information based on the D input and the clock signal. The use of an inverter ensures that the flip-flop operates correctly and avoids the forbidden state.