How to make a 20 LED chaser with 4017 ?
But only 1 led at a time and counting from 0 to 20.

 

plenty on the web -

https://diyodemag.com/education/the_classroom_the_cd4017_decade_counter

 

plenty on the web

I agree they are plenty... but not what I want.
If you mean this cct version:

This type of cct is good as a clock.
Well, When A is clocking B is not doing it sequentially, meaning 1 after 1 (or one after another), but binary, meaning when A is finishing a pass, it will increment B with 1 and then A will start another round.
It is counting 0123456789 in A then 11 in B. (since 10 was lit up until this time) then again 0123456789 in A then 12 in B (since 11 was lit up until this time) and so on.
All I want is an incremental and cursive 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

 

Good question. First I was thinking you just have to cascade 2 x 4017 but that doesn’t work. I’m thinking something along the lines of a single 4017 with an additional flip flop which changes state each time Q0 goes high which takes alternate sets of 10 LED cathodes high with the other set low so they become the set which turns on

 

Good question. First I was thinking you just have to cascade 2 x 4017 but that doesn’t work. I’m thinking something along the lines of a single 4017 with an additional flip flop which changes state each time Q0 goes high which takes alternate sets of 10 LED cathodes high with the other set low so they become the set which turns on

I get is an idea, and I like ideas. Although I did try it already and... problems.
Show me, dont tell me. Make a cct sketch on a paper and photo it, or do it in simulator. Whatever is convenient for you.

 

From the NXP datasheet:

 

Thank you ! It works. It took me a bit to figure out those CP0 and /CP1 here in the sim notations ! But is working now.
I stay on this cct for 2 days and made probably 20 versions, all messed up; until today and I give up and tried the forums.
Wow. And here in 10min puf - done. Haha.
Here is how it looks in Proteus:

I cut some output lines, strategically, to leave only OFF state all the time. Because the IC will maintain at least 1 output Open. So no errors this way. Pretty pretty cool.

 

Show me, dont tell me. Make a cct sketch on a paper and photo it, or do it in simulator. Whatever is convenient for you.

I’m just on my phone so not able to sketch at the moment, but I can explain a bit more clearly. Single 4017 with each output connected to two resistors each connected to two LED anodes but their cathodes connected to two different transistor collectors. A single rising edge flip flop to drive into the base (via a resistor) of one or other of the transistors. Less components maybe?

 

I have these 4 versions and only in a single one I find a similar cct with yours. I could not understand what it is for to be honest.

In this 4017-74HC4017-NXP.pdf - what version is yours with the cct ? Put a link.
I bet I have the same version but mine is chopped off.

 

Take a look at this circuit:



I also attached the Proteus file.

 

Take a look at this circuit:

YES ! Your cct is very cool and is working. Very cool. Dzięki ! (in patriotic red)
I will put your cct in my pile of proteus saves, and probably i will make a movie (maybe) and present it too (as help from Poland).
-
Here is what I did, for the sake of completeness. This is actually a file with -basic- functionality of this logic IC.
I have a folder with them, and I share only ONE ! (only to get an idea how I keep my stuff-is good to give you ideas, for inspiration)

And here is the actual proteus file that contains that specific working cct I got earlier. Again, for completion.

 

The AND gate can be made with two diodes plus one resistor:

 

The AND gate can be made with two diodes plus one resistor:

It is very true indeed and is a good idea, but... on the other side, I have a bit too many AND chips and I NEVER used them beyond testing. So, Im very glad to consume at least 1 chip (with 4 gates in it). And I will have to link all the remaining inputs to gnd or Vcc,I know. I will see how I will make it, is good to have choices.
- Also, when I catch a cct with AND gates in it, I say "Finally", I can use some of those (too many) IC's. Heh.

 

Take a look at this circuit:

I updated your cct with a more flexible one that you can drive 100 leds.
Very cool idea you had with this cct !

 

The numbers on the grid are tiny and are impossible to see. The grid should be turned off.

 

The numbers on the grid are tiny and are impossible to see. The grid should be turned off.

what grid? ---aaaah, that is the background in the simulator.
You probably refer to a better resolution img. Here it is.
Black on white, is how we like it...hehe

I basically switched the original FF with a second 4017 for more outputs, instead of only 2.
The brilliant idea with the FF was that the first 4017 was practically clocking once after he was finishing its 0-9 pass. I was not used to think like that at all.
But with this project here, I am. I was thinking in relation ONLY with the chip itself, and not for external use. I didnt put too much thought into that particular pin. Very briliant idea !
Another interesting design is the - and + on the gates of the mosfets. Usually you have to bring to - rail the gate and usually Im using a 10k resistor linked into the gate to gnd. I was wondering where is that resistor, until I realized that the IC itself is providing that - rail when is switching. Very interesting, again, a novelty for me. Very cool.
I liked the first cct as well, the one from texas instruments. Genius cct. Especially after my many failed tries. Very cool.

 

The RESET pin #15 must be low (0V) for the CD4017 ICs to operate, your first one is floating.

 

The RESET pin #15 must be low (0V) for the CD4017 ICs to operate, your first one is floating.

you are right, and I correct it. But the simulator doesnt seem to care about it. In reality it will not work.
Thats why I dont trust simulators 100%.

 

Take a look at this circuit:

A very interesting finding!
TexasInstruments cct is using 4x4017 ICs + 3xAND gates(1IC) to drive 33 LEDs !
_________Jony130 cct is using 2x4017 ICs + (4xMosfets & res) to drive 40 LEDs !
I'd say Jony130 cct is the most efficient ? Because less ICs and maximum LEDs to drive. Interesting.

 

If the goal is to use only a single CD4017 to sequentially light one of 20 LEDs , without any AND gates, it can be done with a scheme a bit like the one in posts 14 and #17, each count output powering one of two LEDs, with only one connected to negative at any time. and using a CD4013 flipflop to alternate which group of ten has it's DC return enabled, thru an MPSA darlington transistor, and the CD4017 clocked only by the positive transition of the FF's "Q" output.
Only two transistors and two ICs, with no and gates. Probably the power will need to be a bit more than 5 volts for adequate intensity.