Metku.net

MetkuMods
It is currently 19.10.2018 08:15

All times are UTC + 2 hours [ DST ]




Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: LEDs just flicker
PostPosted: 03.04.2004 14:02 
Offline
Junior Modder
Junior Modder

Joined: 01.11.2002 09:18
Posts: 11
Location: Norway
Hi.. Built the circuit now, but I'm having some problems.
All but one led flicker really quickly and really weak. One LED is on constantely though (Pin 11 led, last in series).
At times, for no apparent reason, it switches to another LED (always LED 8, pin 6) for about 50 ms or something, and then go back to the pin 11 led being lit up.

Now, if I remove the cap, all leds light up. If I just let the cap barely touch ground, it starts counting really quickly. Also, when I turn off the power, the sequence is counted, then fades out (caps discharging).

I'm using a 1uF 50V elco cap and a standard 0.25W 47K resistor.

If I put a led on pin 3 of the 555 timer, it flickers on and off like the rest of the leds :/

Now, what's wrong? Any ideas?
Any quick replies would be appreciated as I need to have this circuit built up and working by tueday.

_________________
- Rexxie
Sanity is a full time job.


Top
 Profile  
 
 Post subject:
PostPosted: 03.04.2004 14:08 
Offline
Site Admin
Site Admin
User avatar

Joined: 24.01.2002 10:09
Posts: 4683
Location: Finland
If that led in pin 3 of this 555 flickers on/off it tells us that the timer is giving clock signal to the 4017. Each pulse (led flash) orders the sequence on that 4017 to advance. What kind of leds you are using? 4017 can supply only few milliamps so you can't use any high intensity leds on it without transistors driving them. Check also the power supply and its filters so that the circuit is getting good and steady voltage without ripples.

_________________
Metku | AlltheMods | LedCalc | Teknolelu | AndroidCoding
Main Computer: Intel i5, MSI H55M-ED55, 12 Gigabytes of DDR3, 3 Terabytes of HDD, GTX295 and Benq 27"


Top
 Profile  
 
 Post subject:
PostPosted: 03.04.2004 14:15 
Offline
Junior Modder
Junior Modder

Joined: 01.11.2002 09:18
Posts: 11
Location: Norway
I'm using pretty weak, standard red 3mm leds. They should be fine at 10mA.
I'll try with a different power supply and get back to you.
Thanks for the VERY quick answer :)

By the way, I am aware that the 555 gives pulses, but it seems to be doing it way too fast.. I might be mistaken of course, but it seems really quick.

Anyway, I'll give it a go with another power supply.

_________________
- Rexxie
Sanity is a full time job.


Top
 Profile  
 
 Post subject:
PostPosted: 03.04.2004 14:28 
Offline
Junior Modder
Junior Modder

Joined: 01.11.2002 09:18
Posts: 11
Location: Norway
You were absolutely right. I was testing it on an old ATX power supply, "hotwired". Tested it on my PC and it works fine :)

Thanks alot :D
Now I just need to slow it down a bit ;)

_________________
- Rexxie
Sanity is a full time job.


Top
 Profile  
 
 Post subject:
PostPosted: 03.04.2004 14:33 
Offline
Site Admin
Site Admin
User avatar

Joined: 24.01.2002 10:09
Posts: 4683
Location: Finland
Replace the capacitor with something bigger and it should do the trick. Adjusting the resistor can also help but don't use too high or low values.

_________________
Metku | AlltheMods | LedCalc | Teknolelu | AndroidCoding
Main Computer: Intel i5, MSI H55M-ED55, 12 Gigabytes of DDR3, 3 Terabytes of HDD, GTX295 and Benq 27"


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC + 2 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group