4 Bit Asynchronous Counter using JK Flip-FLop
Two bit Asynchronous up counter that counts from 00 to 11 and back.
JK Flip Flop using SR Flip Flop (implemented with NOR gates)
Reference: The Essentials of Computer Organization and Architecture, 5th Edition. Linda Null and Julia Lobur. Chapter 3, pages 178 - 179.
Sequential circuit used in Exercise 62 from Null & Lobur, Computer Organization and Architecture, 5th Ed.
JK Flip Flop