Master—Slave J-K Flip-Flop

The J-K flip-flop has a toggle mode of operation when both J and K inputs are high. Toggle means that the Q output will change states on each active clock edge.
J, K and Cp are all synchronous inputs.
The master—slave flip-flop is constructed with two latches. The master latch is loaded with the condition of the J-K inputs while the clock is high. When the clock goes low, the slave takes on the state of the master and the master is latched.
The master—slave is a level-triggered device.
The master—slave can interpret unwanted signals on the J-K inputs.
These are not used as often in modern electronics