555 and 4017

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mapleman555

Joined Dec 15, 2014
56
Hello,
I did a project today of connecting a 4017 Decade Counter chip to a 555 timer flashing set-up that I already had and it worked but the 10 LEDs I have hooked up to the 7014 are really week and the single LED I have hooked up to the 555 is strong.
I connected pin 3 of the 555 to pin 14 of the 4017, I grounded pins 8, 13 and 15/4017. I connected an LED to pin 1-7 and 9-11. I grounded pin 16 like the video showed but then non of the 4017 LEDs came on so I took that out.
Any one know why the 4017 LEDs aren't as bright as the 555 one?
Here is the video I followed for the 4017,
.
I can't post a video of my set up but hopefully tomorrow I can take a picture of the set-up.

(Sorry, got the number backwards in the title.)

Thanks

Scott Wang : I corrected the title.
 

MrCarlos

Joined Jan 2, 2010
400
Hello mapleman555
Have You read the data sheets of these devices in particular ??.
Data sheets of 555 say they can Source or Sink 500 mAmp at its output.
While the other (I think you mean the 4017 and not 7014) can only handle about 800 microampers. But LEDs require to light, something like 20 mAmp.

The data sheets for these devices or other You can down load From This link: http://www.alldatasheet.com/
 
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Thread Starter

mapleman555

Joined Dec 15, 2014
56
Well what do ya know, I got it to work right. I unplugged the LED I had hooked to the 555 and now all the LEDs for the 4017 are flashing bright. Some how, at least the way I have it wired, it can't handle both chips with an LED hooked to it. I have a 1000uf cap on it right now but I'm going to use a lower value to speed it up.

MrCarlos,
No I haven't read the data sheet on the 4017, I bought some because they seemed to be a common component in a 555 project, at least for multi LEDs any way.
 

KJ6EAD

Joined Apr 30, 2011
1,581
The output of the 555 can easily drive the attached LED at full brightness and provide a clean clock signal to the 4017 if the circuit is constructed correctly.

The 4017 can only drive around 15mA so if you want more you'll need additional components.

Read the data sheets, preferably before posting your question.
 

Thread Starter

mapleman555

Joined Dec 15, 2014
56
I did a second build of the same 555/4017 set-up as the first one. On the first if I hook pin 16 to power it shuts off the LEDs, on the second one it makes them go ( won't run without it).
Both of them have a random flash sequence. I looked at the data sheet on the 4017 and didn't see anything about a random sequence. I thought it was supposed to be the same repeating pattern. I did see one video where the person used a potentiometer, when he turned it down the lights flashed in the same pattern but when he turned it up they flashed randomly.
Is there a link to an explanation of this in easy to understand terms? I am new at this and a lot of the technical stuff goes over my head.
 

Thread Starter

mapleman555

Joined Dec 15, 2014
56
Remember that stage no. & pin no. are not in straight sequence
True, and now that you mention it I will have to set my second 555/4017 build up so they are in the sequence from 0-9.

What mine does at least looks really random, I could slow it down with a higher value cap to see. I'm using a 47uf on the second one and 22uf on the first.

Well that's interesting. I had a thought while I was typing this so I tried it. It's about outside interference effecting a 555 chip, see this thread, http://forum.allaboutcircuits.com/threads/interference.109922/.
 

KJ6EAD

Joined Apr 30, 2011
1,581
I vote for merging. I hate when someone doesn't like the answers they're getting and opens another thread on the same topic.

P.S. The problems with the circuit are not interference, they're instability due to design and build quality issues.
 

Thread Starter

mapleman555

Joined Dec 15, 2014
56
I hate when someone doesn't like the answers they're getting and opens another thread on the same topic.
It has nothing to do with liking or not liking the answers. It to do with starting a new subject in the same thread.

Merge it, delete it, I don't care.
 
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KJ6EAD

Joined Apr 30, 2011
1,581
It to do with starting a new subject in the same thread.
What 'new' subject? Both are 555 and 4017 sequencer/chaser circuit problems and it seems the second build was only initiated after the first failed and you lacked the ability or persistence to troubleshoot it.

Lest I seem overly harsh, we've seen far worse examples of posters wanting a result sans learning, thought, effort or understanding. Although you've stated your intent to teach yourself electronics by building circuits such as the subject one, you've given no indication of willingness to read the relevant data sheets or show the source schematic you're working from. These are the basis of fruitful interaction on this forum and attempts to get others to voluntarily troubleshoot your work without them will necessarily result in limited success. A trial and error approach, jumping into depths that are over your head and hoping someone saves you before you drown, may eventually work for you but you should understand the reluctance of others to take that journey with you and expect to experience a lot of frustration along the way. Would you consider an alternative learning method, starting with traditional basics and progressing in an orderly way?
 
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KJ6EAD

Joined Apr 30, 2011
1,581
I think you know that wasn't my intention. You can choose to take constructive criticism as it's intended or you can choose otherwise. The quality of help available here is as good as you'll find, but it's your choice.
 
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