Difference Between Ring And Johnson Counter

In digital electronics, there are various types of counters available like ring, johnson, mod etc. But most people are not able to find the difference between the ring counter and the johnson counter because they have very similar concepts and structures also. So here we going to cover the conceptual and useful differences between them.

Ring counter	Johnson counter
1. Number of states is equal to the number of flip-flops.	1. Number of states is equal to twice of the number of flip-flops.
2. It is a MOD-4 counter	2. It is a MOD-8 counter.
3. Last flip flop’s output is given to the first flip flop’s input.	3. Last flip flop’s complemented output is given to the first flip flop’s input.
4. It is also known as a Straight Ring counter, One-hot counter, and Overbeck counter.	4. It is also known as Twisted Ring counter, Creeping ring counter, Switch tail ring counter, Mobius counter, Walking ring counter
5. It is a Synchronous counter	5. This is also a synchronous counter.
6We use Preset (PR) in the first flip-flop and Clock (CLK) for the last three flip-flops.	6. We use Clock (CLK) for all the flip-flops.
7. Circuit diagram:	7. Circuit diagram:
8. Truth table:	8. Truth table:
9. Decoding circuit not required.	9. Decoding circuit required.
10. Hamming distance of used states is 2.	10. Hamming distance of used state is 1.