Are there any major differences between the IC CD4017 and HCF4017 ?

Thread Starter

Ray0911

Joined Jan 27, 2018
2
I am currently working on an electronic dice project and am following this circuit. I am currently using an HCF4017BE for the second IC however it doesn't seem to be functioning as expected in this circuit. If I look at many electronic dice circuit requirements, they usually suggest the use of a CD4017 IC. I am wondering whether this could be the potential problem in my circuit? Should I change ICs or does it not matter?
 

dl324

Joined Mar 30, 2015
12,437
Welcome to AAC!

Circuit in question:
upload_2018-1-27_7-38-20.png
Can you clarify what you mean by "doesn't seem to be functioning as expected"?

Some CD4017 have a schmitt inverter on the clock input which allows slower edges on the clock. I don't recall any other significant differences.

The circuit you referenced has a couple of issues.

The first is that if the timer is a bipolar 555, the HIGH output isn't guaranteed to be high enough to be recognized by CMOS logic. My experience has been that bipolar 555 will drive CMOS with no problems, but it could be problematic if you had a part that was at the minimum spec.

The second is that the circuit is trying to source more current than the CD4017 is guaranteed to provide. I checked two datasheets and minimum current was around 0.2mA, with typical being around 0.4mA. With a 470 ohm current limit resistor, the circuit tries to get around 5mA. Since the outputs are only being used to drive LEDs, that would just result in dimmer LEDs.
 

Thread Starter

Ray0911

Joined Jan 27, 2018
2
Welcome to AAC!

Circuit in question:
View attachment 144493
Can you clarify what you mean by "doesn't seem to be functioning as expected"?

Some CD4017 have a schmitt inverter on the clock input which allows slower edges on the clock. I don't recall any other significant differences.

The circuit you referenced has a couple of issues.

The first is that if the timer is a bipolar 555, the HIGH output isn't guaranteed to be high enough to be recognized by CMOS logic. My experience has been that bipolar 555 will drive CMOS with no problems, but it could be problematic if you had a part that was at the minimum spec.

The second is that the circuit is trying to source more current than the CD4017 is guaranteed to provide. I checked two datasheets and minimum current was around 0.2mA, with typical being around 0.4mA. With a 470 ohm current limit resistor, the circuit tries to get around 5mA. Since the outputs are only being used to drive LEDs, that would just result in dimmer LEDs.
Ok, well I am quite new to electronics but regarding what is wrong with the current 4017 IC, the problem is that 1) the lights do not chase each other, instead they all blink simultaneously. 2) The lights don’t blink at all when the gnd pin from the IC is plugged in. The pulse from the a stable 555 circuit seems to be working fine as I have tested. I have attached an image of what I have done below. I built the two different parts on two different breadboards to see if I could diagnose the problem ( sorry about the mess)

One more note: For the 555 A stable circuit, I have replaced the 100nF for a 100micro farad capacitor as earlier, a pulse was not being generated.
 

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dl324

Joined Mar 30, 2015
12,437
1) the lights do not chase each other, instead they all blink simultaneously.
With a correctly functioning CD4017, only one LED can be on at a time.
2) The lights don’t blink at all when the gnd pin from the IC is plugged in.
An integrated circuit won't work without power. You shouldn't disconnect power or ground willy-nilly. It can cause problems.
The pulse from the a stable 555 circuit seems to be working fine as I have tested.
How can you tell? The whole point is that the timer needs to be at a high enough frequency that you can't "control" which digit it will stop at.
I have attached an image of what I have done below. I built the two different parts on two different breadboards to see if I could diagnose the problem ( sorry about the mess)
Most of us prefer schematics of how you have things connected.
One more note: For the 555 A stable circuit, I have replaced the 100nF for a 100micro farad capacitor as earlier, a pulse was not being generated.
Why would you want to do that? That would decrease frequency by 1000X.
 

bertus

Joined Apr 5, 2008
21,140
Hello,

The leds are supposed to be on all, as long as you press the spin-button.
When you release the spin-button, only one leds should remain on.

Bertus
 

Alec_t

Joined Sep 17, 2013
11,870
The lights don’t blink at all when the gnd pin from the IC is plugged in.
The ground pin (pin 8) and the +ve supply pin (pin 16) should always be connected to ground and +5V respectively, although the posted schematic doesn't show that. From the photos it doesn't look as though pin 16 is connected anywhere. Input pins of CMOS circuits should never be left floating, or you'll get weird results.
 
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