4040 ic

Discussion in 'General Electronics Chat' started by ricker24, Mar 29, 2011.

  1. ricker24

    Thread Starter Member

    Mar 5, 2011
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    0
    Hello, I am going to make a 21 led counter with a reset button and was thinking about using a couple of 4040 IC's. I have found some info on it but am not sure if I can cascade the 2 to get my 21 outputs. If anyone could help or suggest an IC to use it would be greatly appreciated. I have googled 21 led counter and can't really find anything of any use. I made a counter with the 4017 but it only has 10 outputs so as far as I can tell I would have to use 3 of them and I really don't want to do that. Thanks.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    You can connect the Q11 of the first to the clk/ connection of the second 4040.
    The reset lines can be put together.

    Code ( (Unknown Language)):
    1.  
    2. [B]4040[/B]
    3.  
    4.  12-bit asynchronous binary counter with reset.  
    5.     +---+--+---+
    6. Q11 |1  +--+ 16| VCC
    7.  Q5 |2       15| Q10
    8.  Q4 |3       14| Q9
    9.  Q6 |4       13| Q7
    10.  Q3 |5  4040 12| Q8
    11.  Q2 |6       11| RST
    12.  Q1 |7       10| /CLK
    13. GND |8        9| Q0
    14.     +----------+
    15.  
    This way you will have 24 stages.

    Bertus
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    A 4040 is a classic ripple counter, which counts in binary.

    A 4017 is a decimal counter that has been decoded to 1 of 10 outputs on at any one time.

    Fair difference between the two.

    A binary 21 counter has 2^21 counts, or decimal 2,097,152 ( a rather long count). 24 bits have decimal 16,777,216 counts.
     
  4. ricker24

    Thread Starter Member

    Mar 5, 2011
    53
    0
    What chip would you recommend that I use then? I want the led's to light up 1 at a time with every push of a button but want the previous one to go off each time so that only one is lit at a time up to a count of 21. Thanks...
     
  5. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  6. nigelwright7557

    Senior Member

    May 10, 2008
    487
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    Look up Johnson ring counter.
    This has one bit on while the rest are off.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Last edited: Mar 31, 2011
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