Electronics > Beginners

4017 IC Driving LEDs Using Only One Resistor

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HandyAndy:
Hello Everyone!  Long time subscriber, first time on the forums.

I created a basic LED sequence flasher using the 4017 IC chip and a 555 timer to provide a clock signal to it.
Please see attached photo.  The circuit on the left works.  By works I mean it starts by turning on the first led then turning it off and turning on the next led in sequence and repeats the loop.  The circuit on the right will only light the first led and keeps it lit and nothing else happens.  The only differences between them is that instead of using resistors on each LED I replaced them with a single resistor on the top right labeled R13.  I relocated the ground as well to make sure the circuit would have a common ground that wasn't effected by inserting that resistor.  I'm scratching my head now with this and appreciate any help I can get.
Thanks in advance mates and here is the photo:

HandyAndy:
Just thought I would add another photo from Proteus Design Suite with the simulator running to show all the signal markers.  Anything I can do to help you guys help me let me know and thanks again!

oPossum:
You are missing R12 in the second schematic.

HandyAndy:
Thanks, right you are but it doesn't make a difference.  The first pic i posted does the same thing.

HandyAndy:
Correction.  When I add back that resistor now instead of the first LED staying on solid it flashes real fast and never comes back on and none of the others do either.

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