This is a special type of register in which 1 moves in the output in the ring i.e. initially output of 1st FF is 1. On next edge this 1 is transferred to output of 2nd FF while previous output becomes 0. Similarly on next clock output of 3rd FF becomes 1. Similarly it continuous till last FF goes 1. After this 1st FF goes 1 goes again and whole procedure is repeated. This way 1 is moved in a ring as:

i.e.
Clock Q4 Q3 Q2 Q1
Initially 0001
1st tick 0010
2nd 0100
3rd 1000
4th 0001
And so on
Hence we use only 4 states out of 16 states possible in Ring counter.
Or we can say there are 12 unused states in Ring counter.
Circuit diagram to achieve Ring Counter is as:

To start the Ring counter, we firstly give START=0 and then rightmost FF is set and all others are reset and hence initial output is 0001
We can also realize Ring counter using JK flip-flop as:

Application: We can use Ring counter in the system where we have to perform different operations sequentially and repeatedly. Suppose we have to do operations A, B, C & D. Firstly we have to do A, then B, then C, and then D. after performing all operations we have to perform operation A and so on. In this case we can use Ring counter to initiate these operations sequentially.
Excellent read, I just passed this onto a friend who was doing a little research on that. And he actually bought me lunch since I found it for him smile So let me rephrase that: Thank you for lunch! “Whenever you have an efficient government you have a dictatorship.” by Harry S Truman.
Someone necessarily lend a hand to make critically articles I might state. That is the very first time I frequented your website page and to this point? I amazed with the analysis you made to make this particular publish extraordinary. Excellent process!
I’ve been absent for a while, but now I remember why I used to love this website. Thanks , I’ll try and check back more often. How frequently you update your site?
Greetings! Very helpful advice on this article! It is the little changes that make the biggest changes. Thanks a lot for sharing!
Hello! I just would like to give a huge thumbs up for the great info you have here on this post. I will be coming back to your blog for more soon.
Greetings from Idaho! I’m bored to death at work so I decided to browse your blog on my iphone during lunch break. I enjoy the info you provide here and can’t wait to take a look when I get home. I’m surprised at how quick your blog loaded on my cell phone .. I’m not even using WIFI, just 3G .. Anyways, wonderful blog!
I know this if off topic but I’m looking into starting my own weblog and was curious what all is required to get set up? I’m assuming having a blog like yours would cost a pretty penny? I’m not very internet smart so I’m not 100 certain. Any suggestions or advice would be greatly appreciated. Appreciate it
Good post. I be taught one thing more challenging on different blogs everyday. It should always be stimulating to read content from different writers and observe just a little something from their store. I’d desire to use some with the content on my weblog whether you don’t mind. Natually I’ll offer you a hyperlink on your web blog. Thanks for sharing.
I like this website very much, Its a rattling nice post to read and get info .
hello there and thank you to your info – I have certainly picked up something new from right here. I did on the other hand experience several technical points the use of this website, since I skilled to reload the website lots of times prior to I could get it to load properly. I were considering in case your web hosting is OK? No longer that I am complaining, however sluggish loading circumstances occasions will often impact your placement in google and can damage your high-quality score if ads and ***********|advertising|advertising|advertising and *********** with Adwords. Anyway I am including this RSS to my email and can glance out for a lot more of your respective fascinating content. Make sure you replace this again soon..
obviously like your website but you need to take a look at the spelling on quite a few of your posts. A number of them are rife with spelling problems and I find it very bothersome to inform the truth nevertheless I¦ll definitely come again again.
Thanks for another magnificent article. Where else could anybody get that type of info in such an ideal way of writing? I’ve a presentation next week, and I am on the look for such info.
Very instructive and superb structure of subject material, now that’s user friendly (:.