Hi, How can i use a D flip flop 7474, to operate as a "memory" device? example: a user store some password into a system(using d flipflop). now, if he enter the password correctly, he have access to the system, if he enter 3 times wrong, its lock. for the 7474, clk signal must be connect to the clk input of chip only. any suggestion? The flipflop has a PR n CLR, should i make use of that?