16-Stage Decade Counter Chain - Using two 4017 Chips

Picture of 16-Stage Decade Counter Chain - Using two 4017 Chips
I found a way to easily make a decade counter that has more outputs than just 10.

Objective and Motive:
I really like how binary counters can link together in chains. For example, if you have two 8-stage binary counters, you can use them together to easily make a 16-stage binary counter.
I always wanted to do that with decade counters. And today I found a way to do this!
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Step 1: Gather the Parts

Picture of Gather the Parts

• lots of jumper wires
• two 4017 decade counters
• one 555 timer
• two 0.1 µF capacitors (#104)
• one 10 µF capacitor
• one 1 nF   capacitor (#102)
• five 10KΩ (or anything between 4.7kΩ and 22kΩ)
• three N-channel mosfets
• one switch
• one or two breadboards
• one 5V power supply

With these in hand, you should be ready to make a 16-stage decade counter!

Step 2: Examine the Schematic

Picture of Examine the Schematic
Take a look at this schematic to see how the components fit together.
You can click on the schematic picture to see a full-size version.
The 16 green wires on the right of the schematic are the 16 outputs.
I suggest you put 16 LEDs on those outputs with 1KΩ resistors in series to monitor the outputs of this device.

If you don't know how to read schematics, I suggest following this tutorial:
Collin's Lab: Schematics

Step 3: Build Your Circuit

Picture of Build Your Circuit
Now that you have looked over the schematic, you are ready to build the circuit.
Assemble the circuit on a breadboard using jumper wires to connect components.
I recommend referring back to the schematic while building your circuit on your breadboard.

If you can pack your LEDs together tightly, it will save you some breadboard space.
In the end, I had to expand to using a second breadboard because my LEDs took up so much space.
I'm getting some LED bar graphs to fix this problem  :)
iomega15 months ago

Yo! can someone help me convert this into a 12v input? i want to project this to my motorcycle, please help me... sorry I didn't took any electronic course, thanks in advance...

jensenr30 (author)  iomega15 months ago

Hmmm... You shouldn't have to change anything about the circuit. If you look up the 4017 datasheet and the 555 datasheet, you will find that both should work at 12 V.

most 555 chips work up to 18 V. I'm pretty sure 4017 work up to a similar voltage.

However, if you want, you could employ a simple voltage regulator to convert 12 V down to 5 V (look into buying a 7805 voltage regulator). Most 7805 voltage regulators will work with inputs of up to 20 V. With one of those, you can be sure that your power supply is pretty close to 5 V and well regulated.

I hope that was helpful!


b8el0186 months ago

I think can use only 1 resistor for all the LEDs because there is only ever 1 LED on at one time. Nice circuit though :)

jensenr30 (author)  b8el0186 months ago

That is an excellent observation.


TimS97 months ago

Great idea. I have made this circuit & it works great but if you get the amber light time right, the red & green lights are too short, the whole sequence is too quick. I need to extend the red led count by 4 counts & the green by 4 counts & using your idea I think would solve the problem, I can follow a circuit diagram fine but trying to work this out, well when I was young most things still had valves!!!!!


jensenr30 (author)  TimS96 months ago

That sounds interesting. I think you could do that if you slightly modified my circuit. (i.e. make it an 18-step counter rather than a 16-step one)

TimS9 jensenr306 months ago
​As I say I can follow a diagram fine but need a little help in trying to adapt the two circuits. You say to use 3 N-Channel Mosfets could you be a little bit more precise as to how many amps & volts you used, I looked on one site & there were 43 different types ranging from 12v to 500v. Whatever I do the power source will be a 12v DC transformer which will be running various other lights & signals at the same time.

jensenr30 (author)  TimS96 months ago

To change it to an 18-step counter, route the reset signal come from pin Q9 instead of pin Q8. That will make the counter have 18 steps rather than 16.

halamka1 year ago
Great -- now hook it up to a memory chip and computer screen .
gprakash11 year ago
Hai friend nice projects you done, and you have a good knowledge,please do me a favour, that how can we construct a circuit that it should be operated when a push button is pressed so that the relay in the circuit will stay on till the push button again pressed, here we should use only a push button which makes a circuit connected when button pressed, and breaks the circuit when removed, please if you have a circuit please send me a mail to
Teslaling2 years ago
That is a brilliant design! I think that it is a very efficient way to "add" counters together. Since they count independent of each other, I assume that means that you could also count odd numbers too. For example if I needed to count to 13, I could stop one on the 8th output and the other on the 7th output right?
jensenr30 (author)  Teslaling2 years ago
Exactly right!
On counter could count to 7 (stop on eight) and the other could count to 6 (stop on 7) so that the total equals 13.
It seems you understand the concept of this device perfectly! :D
I'm glad I was able to show how my machine works.
pfred22 years ago
This is interesting. I would have thought the carry out pin would have been used to clock the second counter. I often like using a 74154 if I need 16 outputs too. This way is more compact.
jensenr30 (author)  pfred22 years ago
ooh. The 74154 looks really nice. I might have to use this for my drum machine instead...
Thanks for the info!