# Clock frequency divider circuit

#### Huzaifa Asif

Joined Mar 22, 2015
11
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

#### Alec_t

Joined Sep 17, 2013
11,797
Here's a divide-by-six using an inverter

#### Alec_t

Joined Sep 17, 2013
11,797
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.

#### Huzaifa Asif

Joined Mar 22, 2015
11
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.
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.

#### absf

Joined Dec 29, 2010
1,949
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
Look at page 4 of the datasheet attached.

Allen

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#### Huzaifa Asif

Joined Mar 22, 2015
11
Look at page 4 of the datasheet attached.

Allen
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

#### absf

Joined Dec 29, 2010
1,949
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

#### Huzaifa Asif

Joined Mar 22, 2015
11
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

View attachment 82608
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

#### Alec_t

Joined Sep 17, 2013
11,797
Hint:
A flip-flop (JK or D or T type) can divide by two.
6 = 2 + 4.

#### Huzaifa Asif

Joined Mar 22, 2015
11
Hint:
A flip-flop (JK or D or T type) can divide by two.
6 = 2 + 4.
Can I 'OR' the output of 1/2 CLK and 1/4 CLK?

#### Alec_t

Joined Sep 17, 2013
11,797
The logic combination you need is 'AND', not 'OR'.

#### Huzaifa Asif

Joined Mar 22, 2015
11
The logic combination you need is 'AND', not 'OR'.
1/4 * 1/2 gives 1/8 doesn't it?

#### Alec_t

Joined Sep 17, 2013
11,797
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.

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