In the SR flip flop an uncertain state occurred. This can be avoided by using D flip flop. Here D stands for “Data”. It is constructed from SR flip flop. The two inputs (S &R) of the clocked SR flip flop are connected to an inverter.
It is one of the most widely used flip – flops. It has a clock signal (Clk) as one input and Data (D) as other. There are two outputs and these outputs are complement to each other. The symbol of D flip – flop is shown below.
D flip – flop using NAND gates is shown below.
D flip flop will work depending on the clock signal.
When the clock is low there will be no change in the output of the flip flop i.e. it remembers the previous state.
When the clock signal is high and if it receives any data on its data pin, it Changes the state of output.
When data is high Q reset to 0,while Q is set to 0 if data is low.