# JK flip flops

#### Keith Kinsey

Joined Dec 14, 2006
4
Can some please help me in desiging a circuit using 2- 7476, 1- 7400, and 2- 7447? I have to build a circuit that counts to 12 and resets to zero. I also have 2- 74LS30 and 2- 7 segements.

#### beenthere

Joined Apr 20, 2004
15,819
Hi,

I moved this over here because it sounded like an assignment.

Yes, we can help, but won't do the work for you. Have you made any progress on this circuit so far? Working it out on paper with logic symbols ( I prefer MIL-STD 806C ) usually lets you see how to hook things up.

#### Keith Kinsey

Joined Dec 14, 2006
4
Hi,

I moved this over here because it sounded like an assignment.

Yes, we can help, but won't do the work for you. Have you made any progress on this circuit so far? Working it out on paper with logic symbols ( I prefer MIL-STD 806C ) usually lets you see how to hook things up.
Yes I did tried, but It does not work. What is MIL- STD 806C and how can I get it?

#### beenthere

Joined Apr 20, 2004
15,819
Hi,

That is a clooection of symbols for designating logic elements, like AND gates and so on. It just lets you draw the arrangement of logic gates in the circuit.

What did not work?

#### JoeJester

Joined Apr 26, 2005
4,390
Keith,

Put up your circuit drawing and the members can review your drawing.

Once any errors are corrected in the drawing, you'll be halfway there.

#### Keith Kinsey

Joined Dec 14, 2006
4
My drawing is putting the JK's in asyncronous. I used the 74LS30(8 input NAND) to each of the outputs of the JK. Like Q,Q*output. I also used the 74LS00 ( quad 2 input NAND) on the output of the 74LS30. I'm also using another JK to drive the other 7 segement, But when it counts 0-9 the LSB stays to 1. How do I get my MSB to reset after the first cycle? 0-9 and then 0-1.

#### beenthere

Joined Apr 20, 2004
15,819
Hi,

Bet we could tell if we had a schematic to look at.