strange behavior

Discussion in 'General Electronics Chat' started by matty204359, Apr 8, 2011.

  1. matty204359

    Thread Starter Member

    Apr 6, 2011
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    my 4017 ring counter is randomly flashing its outputs hooked up to leds. I thought it was lack of a decoupling capacitor but having added one its still acting strangely and pretty much ignoring my clock signal. I mistakenly hooked up one of its outputs to the 5 volt rail. are there no protection diodes? could I have destroyed it?
    I have attached a video of the IC

    http://forum.allaboutcircuits.com/attachment.php?attachmentid=29395&stc=1&d=1302273456
     
    Last edited: Apr 8, 2011
  2. Audioguru

    New Member

    Dec 20, 2007
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    The inputs of a CD4017 cannot flash anything. Its outputs can flash LEDs.
    With a 5V supply its shorted output current is only about 4mA so it won't cause damage if an output is shorted to +5V. Look at its output currents on Texas Instruments datasheet.

    You didn't post your schematic so we don't know if your clock is an extremely noisy 555 oscillator that must have two decoupling capacitors as is recommended on its datasheet.
     
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  3. matty204359

    Thread Starter Member

    Apr 6, 2011
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    Sorry my mistake. What I actually meant was flashing its outputs. Originally my clock was an arduino (micro-controller platform). but given its strange behavior and debugging my program for hours did not fix the behavior I decided to use my clock pulse from a 32768Hz crystal divided by a CD4060 and CD4040 to 1Hz. I have attached a small video (.avi format) taken with my cellphone to my OP(Original Post)
     
  4. Audioguru

    New Member

    Dec 20, 2007
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    It looks like the clock beats fast then stops, over and over.
    The breadboard is a lousy way to make a circuit. Its tangled wires and its high capacitance between rows of contacts couple signals together. The tangled wires are antennas that pick up mains hum and all kinds of interference. The contacts guarantee an intermittent circuit.

    Post the schematic of the oscillator and counters connected to the CD4017. Does it also make the "strange behaviour"? What kind of 5V supply?
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    Schematics are the language of electronics. One schematic can replace 20 posts on a thread.

    I'll disagree with AG about protoboard, with a proviso. Wiring should be as short as possible, as in flat on the board. The illustrations I draw are accurate, the wires really look like I draw them.

    For example...
    http://www.allaboutcircuits.com/vol_6/chpt_8/7.html

    I have made many 4017 circuits on protoboards that worked well first time, every time.

    My first guess with your circuit is you probably need filter caps, both 220µF and 0.1µF (the latter on the power supply pins of each chip).
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    The video shows a tangled mess of long wires all over the place on the breadboard which is why I mentioned it. The wiring was thrown together with no planning.
    But I have seen many messy stripboard and perfboard circuits the same that also didn't work.
     
  7. matty204359

    Thread Starter Member

    Apr 6, 2011
    105
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    What software would you suggest I use. I downloaded Eagle but I don't exactly know how to use it yet.

    I will try to draw the schematics for the counter circuit up with eagle. The power supply is a 5volt LG phone charger with the USB connector cut off. The 32768Hz divider/counter circuit has been running for months with no odd behavior I can detect however, I only have a led indicator. I would love to have a oscilloscope but even the cheapest oscilloscope are not exactly in my price range. At a glance I would say its giving me a 1Hz signal.


     
    Last edited: Apr 8, 2011
  8. Audioguru

    New Member

    Dec 20, 2007
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    Bill and I use Microsoft Paint to make schematics.
    Straight lines are made with the shift key pressed.
    Copy and paste parts from other schematics and datasheets.
     
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  9. Wendy

    Moderator

    Mar 24, 2008
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    You can grab my templates I use to draw schematics here...

    Introduction and PaintCAD

    Here is how I use them...

    Bill's Albums

    And this is my blog with other articles...

    Bill's Index

    Basically AG agree on the wiring issue. There is an old rule I figured out in college, the neater you make it look, the more likely it will work first time. I make the wires to length and keep them in a kit box, but you can also buy them from many sources.

    [​IMG]

    http://www.radioshack.com/product/index.jsp?productId=2103801#

    The bypass capacitor issue has been made a sticky...

    Decoupling or Bypass Capacitors, Why?

    I have several schematics for 4017 and its cousin, the 4022, in this article...

    LEDs, 555s, Flashers, and Light Chasers, Chapter 11, Making Patterns
     
    Last edited: Apr 8, 2011
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  10. matty204359

    Thread Starter Member

    Apr 6, 2011
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    [​IMG]


    ^^^like this? I hope so that took me like an hour to make!
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    Simply copy and paste into Paint the images with pins names from the datasheets of the ICs then add a couple of lines, resistors and capacitors.
    It takes about 2 minutes.
     
  12. matty204359

    Thread Starter Member

    Apr 6, 2011
    105
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    Lmao, Live and learn.


    Real life pictures of my clock circuit
    [​IMG]

    [​IMG]
     
  13. Wendy

    Moderator

    Mar 24, 2008
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    Does it work now?

    I'm not trashing you, but what you did to that crystal is a crime. :D Bending the leads right next to where they go into the case breaks both the seal and the leads as often as not.

    It gets much easier with practice, that would have taken me 10 minutes, tops. The 4060 was lifted straight from one of the prints, so lining up the 4040 was the only hard part.

    What you have there is the core of a pretty good timer. Use a diode AND gate and you can send a 1 second signal on any amount of time up to 2 hours 16 minutes and 32 seconds.
     
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  14. matty204359

    Thread Starter Member

    Apr 6, 2011
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    Well thanks for letting me know about my mistreating that crystal. If you never told me I maybe never would have known till I went to make my final product.

    I'm just getting around to wiring up the ring counter now. I'll update once I've finished wiring it up to let you know If fixing the birds nest of wires helps. I'm also going to move it closer to the divider since some one mentioned the solderless bread board might be the problem.


    You are correct I did lift your 4060 circuit. All I had to do was change the capacitor values and resistor value to match the ones I'm using. In time i'm sure I will get faster at making the drawings. I have some 1n4148 general purpose diodes I have yet to use.
     
    Last edited: Apr 8, 2011
  15. Wendy

    Moderator

    Mar 24, 2008
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    Works that way for all components, transistors, LEDs. I made the same mistake with one of my labs in college. The teacher forgot I had not had the class where that had been explained, and scorched some hide. He was (is?) a good teacher.

    I'm not sure what you're going for, take a look at Figure 9.1 of LEDs, 555s, Flashers, and Light Chasers. With a little planing protoboards can look as good as the final product.

    [​IMG]

    The 4017 and 4022 are close cousins, one has 8 leads out, the other 10.
     
  16. matty204359

    Thread Starter Member

    Apr 6, 2011
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    Thanks everybody who posted. I got the 4017 working and acting predictably. It would appear you guys were right about the wires being too long.
     
  17. Wendy

    Moderator

    Mar 24, 2008
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    Thanks for the feedback, most times we never get it. Between the two the filter caps are more important, but both count.

    One of my future articles will be a 4060 time base, similar to yours. Another user pointed out the (now obvious) fact the crystal circuit would work on the protoboard.

    The reason I had doubts is protoboards are notoriously bad at high frequencies (think RF). All those parallel runs are like 5pf caps next to each other. The system is simple enough though it is worth it, it is just something to be aware of.
     
  18. matty204359

    Thread Starter Member

    Apr 6, 2011
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    Well before I joined this forum I had read numerous forum posts here (AKA "lurking"). With that in mind I would like my threads to be as helpful as possible for other people to read.:)
     
  19. retched

    AAC Fanatic!

    Dec 5, 2009
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    Now THATS the attitude all OP's should have.

    Cheers to that, friend!
     
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