Master and slave flip flop
A master and slave flip flop has two clocked flip flops, known as the master and the slave. When the lock is high it is called the master, and when it is low the slave flip flop changes and becomes active.
The output of the master flip flop is set and reset according to the state of the input.
The final output of the master-slave flip flop is that of the slave flip flop.
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