• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

more on 555 and 4017

Status
Not open for further replies.

daviddoria

New Member
i now have a working 555 yay!

ok so now i am connecting 8 and 13 of th 4017 to ground, 14 to 3 from the 555, 16 to Vs, and led to pin 3 - then to ground, and pin 2 to 15 to reset it after 1 output.

is there anything wrong with that? i'm going to try to draw it for you in my new software :)

http://www.bandtank.com/~calculusap/oscillator.ewb

that looks pretty crappy... how do you make the lines not go through stuff?
 

Gene

New Member
Congrats! Sorry I couldn't get your Elect. Workbench file but your description sounds fine. Move that pin #15 connection up a bit, add some LEDs, and turn that 4017 loose to run. I appreciate your posting as so many people ask a question and never reply. You never know if they ever came back and read the replies - strange.
 

daviddoria

New Member
haha.

so i can't seem to get the LEDs on the counter to turn on..... i am going to go try a transistor now... but i thought the output of the counter was enough to turn on an led... if that doesn't work i'll post again to see what else i can do.

thanks
david
 

Gene

New Member
Since I can't see your circuit, I don't know what your power source is but a 555/4017 powered by a 9 volt battery should produce about 5 volts at pin 3 of the 4017 (plenty to burn out an LED without a dropping resistor).

Maybe you could PM me with your .ewb file as an attachment - don't care if it's crappy.

I am assuming from your first post that you have confirmed a pulse comming from the 555 - check your connections.
 

daviddoria

New Member
hahahaha i got it!!!

gene, again i'm almost sure i saw that the 4017 has internal ouput resistors... i'll try to find it again.

my problem was simply with how i was connecting the leds to the breadboard. they were shorting themselves! i'll be darned!

well it works now, time to put it on a protoboard :))

i'll take a video and send you when i'm done (might be a couple days)

thanks a million!
david
 

Gene

New Member
The 4017 has a current limitinng circuit which is marginal-at-best for operation at 5 volts. You can also limit the output by connecting the input pulse through a resistor. The easiest way is to connect your LEDs directly to the output pins of the 4017, tie the (-) side of the LEDs together, and run that through one resistor to ground (this is ususlly possible since only one LED is lit at a time).

There is no need to do the video for me - just glad you are up-and-running. BTW, before you solder the thig up, now would be a great time to experiment with the different functions of the 555 and 4017 (pulse timing, timing vs. astable operation, reset after different counts, and cascading multiple 4017s). Enjoy!
 

daviddoria

New Member
only one more question!
i got this working several times now, that means i understand, yay!

i am using Trax Maker to draw. I noticed that on my 4017, there is no pin 8 and no pin 16. these are Vs and ground. when i hit "simulate" it doesn't work (i'm guessing because the chip isn't getting power)

i also noticed on a drawing by kinaljp that he was missing the same pins...
is there a way to add pins? are they left off for a reason?

david
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top