Hello. I am new to the forum. As the title suggests, I would like to design an asynchronous simple 4-bit BCD counter with LED's. From what I understand, I will need 4 J/K flip flops (1 for each bit), 4 led's, a battery, and then possibly some resistors. Also, I may consider also adding a synchronous counter switch so I can go from sync to async if it's not too much trouble. Any help would be awesome. I'm not a big fan of radio shack, but I will go there if I have to.
EDIT: As a side question, does the clock inputs have to be at a certain frequency or can it just be a switch that you control up and down for 1 and 0?