# JK flip-flop: What is the difference between clear and J=0, K=1, rising clock?

I'm trying to create a Program Counter using some JK flip-flops.

I have two different way to do that:

• Use some 74LS73 (dual JK flip-flop with clear):

• Use both 74LS10 (triple input NAND) and 74LS00 (double input NAND):

Using the first integrated circuit will be easier, but this isn't the problem.

My doubt is about the Clear pin in 74LS73: I know it will reset the flip-flop but also the combination J=0 and K=1 on a rising clock edge should do it...

So, what is the difference between the Clear pin and J=0, K=1, rising clock?