 ### Network # How does a decade counter IC 4017 works?

Feb 14, 2018
40
Like the title how it works?

Only thing i understood is that it give an output based on pulses?
What is a pulse? how are you supposed to send specific pulses?
I need a more general explanation on IC.
Only thing i understood is that NAND AND OR Gates and some basic others.
I understood the thing with logic 0 and logic 1.
With the 5 voltage thing as 1 and the results.
For example AND 0 and 0 is 0 . 1 and 1 is 1. 1 and 0 is 0.
But nothing else about the ic i dont understand

#### (*steve*)

##### ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
the counter counts edges.

The 4017 advances on the rising edge of a clock pulse. That means it counts up by 1 each time the logic level changes from a 0 to a 1 on the clock input.

A pulse is the logic level changing from 0 to 1 and back to 0 (it can also be the reverse of this (1 to 0 to 1) but that is a negative going pulse and lett's ignore that for the moment because I'm going to assume you haven't followed me).

For all the details, google for a 4017 datasheet. I expect you won't understand it, but that's the way you get this information.

Feb 14, 2018
40
the counter counts edges.

The 4017 advances on the rising edge of a clock pulse. That means it counts up by 1 each time the logic level changes from a 0 to a 1 on the clock input.

A pulse is the logic level changing from 0 to 1 and back to 0 (it can also be the reverse of this (1 to 0 to 1) but that is a negative going pulse and lett's ignore that for the moment because I'm going to assume you haven't followed me).

For all the details, google for a 4017 datasheet. I expect you won't understand it, but that's the way you get this information.
Then how are you supposed to control the pulses?What do i need to put in the clock input to control the pulses.
For example i saw flashing leds in a order how are you supposed to make it.

May 20, 2017
1,217

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,482
To understand how any counter works you need a basic understanding of flip-flops (not the sandal type ) which are the memory elements used in counters. From these flip-flops a so called state machine is built were with every clock pulse the state (aka count) is advanced. Different types of counters exist that count in different ways. The 4017 in particular is based on a so called johnson counter. It has 5 flip-flops plus a few logic gates which decode the flip-flop's states into the 1-out-of-10 code displayed at the 4017's outputs.

Here's a simple introduction to the 4017.

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