# Clock frequency divider circuit

Discussion in 'Electronics Resources' started by Huzaifa Asif, Mar 22, 2015.

1. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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In order to create a divide-by-two circuit, we only use an inverter that is connected between the output and the input of a flip flop.

What if we want to create a divide-by-six circuit? Cant we use an inverter for that?

Regards

2. ### Alec_t AAC Fanatic!

Sep 17, 2013
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Here's a divide-by-six using an inverter

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3. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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I am permitted to use only flip flops.

4. ### Alec_t AAC Fanatic!

Sep 17, 2013
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A pity you didn't say that in your original post . This is clearly a Homework problem. You need to state exactly, in full, the conditions imposed on you.

5. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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Sorry about that however I did mention about flip flops in my question but didn't explicitly stated that we are permitted to use flip flops only.
That's the only condition that's imposed on me.

6. ### absf Senior Member

Dec 29, 2010
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No kidding. I didn't even know it was possible.

Allen

7. ### absf Senior Member

Dec 29, 2010
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Look at page 4 of the datasheet attached.

Allen

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8. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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Is D-flip flop different from J-k flip flop? I couldn't understand how it's working.

Check the third figure where three flip flops are being used with each dividing the clock frequency by its half. I want to make a similar circuit but it's able to divide the clock frequency by six (1/6).
http://www.electronics-tutorials.ws/counter/count_1.html

9. ### absf Senior Member

Dec 29, 2010
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OK, I use 3x JK flip flop and connected them as T-flip flips as in your link. Then I add a NAND gate to reset the flip flops when it counts to 6 (see circuit attached). So it would be counting from 0 to 5 (i.e. Mod 6).

Are you able to do it with 3x D-flip flops?

Allen

10. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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I haven't studied JK flip flops so I can't really understand. I shall be grateful if you can tell me how it works using D-flip flops

11. ### Alec_t AAC Fanatic!

Sep 17, 2013
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Hint:
A flip-flop (JK or D or T type) can divide by two.
6 = 2 + 4.

12. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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Can I 'OR' the output of 1/2 CLK and 1/4 CLK?

13. ### Alec_t AAC Fanatic!

Sep 17, 2013
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The logic combination you need is 'AND', not 'OR'.

14. ### Huzaifa Asif Thread Starter New Member

Mar 22, 2015
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1/4 * 1/2 gives 1/8 doesn't it?

15. ### Alec_t AAC Fanatic!

Sep 17, 2013
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In algebra yes; but simply ANDing the outputs of two cascaded flip-flops will give a pulse period 1/4 the input clock pulse period, with a 1:3 mark/space ratio . You need AND logic to detect a count of 6 and then immediately reset the count to zero.

Last edited: Mar 24, 2015
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