Verifying 4017 Decade Counter

Thread Starter

leo.leo.leo

Joined Apr 4, 2017
19
Does anyone know of an extremely simple circuit I can use to check if my 4017 is working?

I've been trying to build a circuit from a book with a CD4017BE IC.

First time through, the circuit did not work. It was supposed to light up 10 LEDs in sequence, at first rapidly, and then slow to a stop). In my circuit, LED 1 lit up brightly and stayed on. The other LEDs stayed off (or were imperceptibly dim).

I tried to simplify the circuit using a push button instead of a clock signal and now nothing lights up at all.

I would like to find a super-simple 9v circuit I can use to test if it is working or if it's a dud.
 

dl324

Joined Mar 30, 2015
10,072
Tie reset and clock enable LOW, apply a clock to the clock input, and measure each output.

If you use a switch and don't debounce it, you'll have to contend with switch bounce.

You could make a slow clock signal with a 555 timer or a Schmitt inverter
 

Thread Starter

leo.leo.leo

Joined Apr 4, 2017
19
Switch bounce would be fine, as long as I get some confirmation that the thing is running.

I should have mentioned that I'm new to this so links to a diagram or some patient step-by-step instructions (as though spoken to a child) would be a huge help.
 

bertus

Joined Apr 5, 2008
20,335
Hello,

As you did not post a schematic of your circuit, only general info can be given.

Pinout of the 4017:

HEF4017_pins.png

4017 function:

HEF4017_function.png

Attached full datasheet.

Bertus
 

Attachments

bertus

Joined Apr 5, 2008
20,335
Hello,

I assume you connected pin 7 to the ground (minus of the powersupply).
When this pin is floating, the counter will not work.

Bertus
 

Thread Starter

leo.leo.leo

Joined Apr 4, 2017
19
Yes, I did spot that and connected pin 7 to ground.

I may have made some other blunders elsewhere but after checking several times, I didn't find any.
 

crutschow

Joined Mar 14, 2008
24,413
Well if everything is connected correctly and it doesn't work, then you would seem to have a bad chip.
Measure all the pin voltages and post them here.
 

Thread Starter

leo.leo.leo

Joined Apr 4, 2017
19
While I was testing the pin voltages, one of the LEDs lit up. Turns out that putting pressure on the chip fixed the issue. Maybe one or more of the pins was not seated properly in the breadboard.

Thanks everyone!
 
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