Figure 5-33(a) shows the symbol for a J-K FF that responds to a NGT on its clock input and has active-LOW asynchronous inputs. The external active- LOW asynchronous inputs are labeled PRE
Asynchronous inputs in the flip-flop sequential circuit: study notes
JK Flip Flop and SR Flip Flop - GeeksforGeeks
Solved Switch PRE D CLK 7474 CLR Switch Table 4: Truth Table | Chegg.com