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555 timer output amp

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Hi Ron:
I have bread boarded my design and am having trouble.
I am using the circuits shown in:
I don't get what I expect as outputs.
I have tried the circuti with and without the debounce part and still doesn't what i expect.
What I expect is that when I toggle the switch the counter should increment one count with each toggle.
I have connected the reset pin(15) to ground and connected the enable pin (13) to the output I want.
What happens is that on the first switch toggle I get the chosed output to go high.
I am using only one LED and connect it to the chosen output.
Also, My information says the count can be halted by having the enable pin go high but it doesn't. It goes high when ground is connected to it.
Any thoughts are greatly appreciated.
Regards,
Richard
 
Getting ready for work but real quick I believe you want to tie Enable to Ground. Since the 4017 (when enabled) sequentially increments up with each positive clock transition and the outputs go high as soon as the Enable pin goes high everything will halt. I believe everything will just stay in that state. Try tying the RST to one count above what you want for a max count. This makes a "count to N and reset" configuration. As time allows at work I will try and post more.

Ron
 
Hi Ron:
I think I made some progress last night after posting.
I tied Enable to Gnd and RST to one count above what I wanted and the circuit was working.
I didn't detect that the counter was being reset but it was late, 1:00 AM, and I thought I should go to bed.
It is my understanding that in this configuration the counter keeps counting. My information say that if Enable is tied to "count to N" the count will halt but I'm not sure this is happening.
What I want is for the counter to stop counting at "count to N"
I will work on it today. I'm learning a lot and I think I don't recognize all that is going on. I just need to keep at it.
Regards,
Richard
 
Hi Ya Richard

Yes, that makes sense. For a count to N and halt the 4017 would have pin 13 (clock enable) tied to N. Since count only takes place when the CE is logic low, when the count gets to N and N goes high then the CE is disabled and a reset either manually (push button) or electronically is required. Reset, pin 15, is normally tied low and a high causes a reset. So for count to N and recycle then RST pin 15 would be tied to N.

Ron
 
Hi Ron:
Still having problems.
I can't get a consistent output. Makes me think there is contact bounce but I can't get the debounce circuit to work.
Is it possible for me to call you? I realize it's an imposition but I feeel if I could talk to someone it would be a big help.
If its possible please email me and I will call you at your convenience.

Regards,
Richard
 
Last edited:
I sent you a PM with my work phone. I am easier to get there. :) Do yourself a favor and remove your email from your post. You should have my PM with my office number which is right to my phone. If you miss me (I run around the plant a lot) just leave a call back number.

Ron
 
Can you make it about 1 PM my time? Noon I am seldom in my office.

Later
Ron
 
OTAY! :)

Ron
 
Hi Ron:
Here's the latest. I think the problem is in the switch and I can't get the debounce to work.
I only have a VOM but of course can check voltage levels
The way I get the counter to work is by triggering a 555 with a wire from Ground to the 555 trigger input. The 555 is set up
as a monostable timer. The 555 output goes to the counter clock input. If I touch the trigger wire to ground (count 1), wait for the 555 to time out then touch the wire to ground again (count 2) etc I cn get the counter to count. If I connect the counter Enable to the count I want to stop at it will stop at that cound.
I can't reliably repeat this sequence if I us a switch connect to ground to trigger the 555 and as I said attempts to debounce don't work.

Talk to you at 1:00

Regards,
Richard
 
I assume you have tried some switch debounce? Something similar to the attached?

The problem is that when a circuit like the attached will not overcome the switch bounce then we get into adding a schmidt trigger IC and the parts count starts to grow.

I will make every effort to be around my desk this afternoon. Hopefully no meeting or other things will surface. If I do miss you just leave a voicemail and I'll get right back to you.

Ron
 

Attachments

  • deBounce Ckt.gif
    deBounce Ckt.gif
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Hi Ron:
Very nice to talk to you. Thanks for taking the time.

I now have my circuit working, Hurray!!

But, one question: I have read that any unused 4017 outputs should be connect to ground.
Is this a good thing to do?
I am using the counter to count to 7 and then reset. All other outputs are not connect to anything.
Best regards,
Richard
 
No, that is not true of the 4017. Not that I am aware of anyway. The unused outputs will just remain at a low. I am pleased that you got things working. My pleasure for any help that I was.

Ron
 
Hi Ron:
Hope all is OK with you and yours.
I had my first circuits up and running and started to add the next circuit and am having trouble.
What's frustrating me now is I have 2 volts on the ground line and it appears on just about every pin on the 555 and 4017.
I've checked all that I can that might cause this such as touching wires and can't find anything.
Comments?

Thank you

Best regards,
Richard
 
Hi ron:
Well, after much troubleshooting I found the problem.
Broken trace on the PC board ground line.
I fixed that and while I haven't had time to check everything the 2 volts on the ground line is gone and a quick check shows things to be OK.

Best regards,
Richard
 
Hi Richard

Things in my little world are good. Both wife and I have cough and cold so a little misery here. :)

Anyway, real glad that you found the problem as I was stumped after reading the first post on the problem.

Later
Ron
 
Hi Ron:
Sorry to hear you're a little under the weather. The Cleveland weather can be unsociable.
I thought I was out of the woods on my last post and for the most part are but I have one transistor that I think is good but it's got 2 volts on its collector when it should have 5. However, I'll figure it out.
Best regards,
Richard
 
Let me know. :)

Ron
 
Hi Ron:
Since most of the circuit is running I've decided to stop for a while and concentrate on building the mechanical parts of the system. There are four motors to install and some questions about how long each should run so I will address these issues and adjust the electronics as needed.
I'll post progress.

Best regards,
richard
 
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