CD 4017 Reset issue

Thread Starter

rovies

Joined Nov 26, 2019
15
Hi, I have built the attached circuit which works, except for one issue. If the outputs of each 4017 are connected to LED's they all light up, and that is fine.
The problem is that I have to connect outputs from each 4017 together, so that they light up in a predetermined sequence.
For example, the output from pin 3 on the first counter, must be connected to output 6 of the second counter. Other examples are pin 2 of the first counter must connect to pin 5 of the second, and pin 4 must combine with pin 1. This is shown on the schematic. (apologies it is drawn using Excel)
The connection of these pairs of wires all work, except for Pin 3 of the first 4017 with Pin 6 of the second. What happens when I connect these outputs is that all the led's stop blinking, except for the output from 4017 (1) which stays onPartCD4017Drawing.png
I can't help thinking that the output of pin 3 of 4017 (1) is being messed up by the reset signal of pin 15 on 4017 (2)
Any help on how to overcome this will be greatly appreciated
 

AlbertHall

Joined Jun 4, 2014
8,840
Pins 3 and 6 feed an LED and also feed the reset of a '4017. The LED will prevent the voltage going to a high enough voltage to be recognised as a logic '1'.
What supply voltage are you using?
 

AnalogKid

Joined Aug 1, 2013
8,230
Do you have current limiting resistors in series with each LED?

Please post the complete schematic so we can see how the LEDs are affecting the rest of the circuit.

ak
 

Tonyr1084

Joined Sep 24, 2015
3,942
From what I believe I can see - your reset from CD4017-2, pin 9 should go to BOTH resets. Otherwise when CD4017-2 goes into reset it remains in reset holding CD4017-1 in the reset mode. Until you clear CD4017-2 your chips won't run beyond that point.
 

Tonyr1084

Joined Sep 24, 2015
3,942
Are these LED's Bi-Color? I ask because I see the output of (for instance) pin 2 (17-1) through two opposing LEDS to pin 5 (17-2). With no ground the LED's should not light up. Unless you're using pin 5 as ground for when pin 2 is high. But then the associated LED would block; unless it's bi-colored.

As for resistance - I assume you've not drawn in the resistors because of the complexity of doing this diagram on Excel; which I commend you on. You've done quite a good job. But Excel has its limits. If you have paint brush, give that a try. Draw a single element then copy and paste it as many times as you need. Just a suggestion.
 

eetech00

Joined Jun 8, 2013
1,741
Hi, I have built the attached circuit which works, except for one issue. If the outputs of each 4017 are connected to LED's they all light up, and that is fine.
The problem is that I have to connect outputs from each 4017 together, so that they light up in a predetermined sequence.
For example, the output from pin 3 on the first counter, must be connected to output 6 of the second counter. Other examples are pin 2 of the first counter must connect to pin 5 of the second, and pin 4 must combine with pin 1. This is shown on the schematic. (apologies it is drawn using Excel)
The connection of these pairs of wires all work, except for Pin 3 of the first 4017 with Pin 6 of the second. What happens when I connect these outputs is that all the led's stop blinking, except for the output from 4017 (1) which stays onView attachment 193125
I can't help thinking that the output of pin 3 of 4017 (1) is being messed up by the reset signal of pin 15 on 4017 (2)
Any help on how to overcome this will be greatly appreciated
Hi

Please describe the LED sequence your trying to implement.
It isn't clear from your block diagram (the circuit looks a little strange).

I've redrawn your diagram in schematic form. I'll revise it once you've described LED sequence your trying to implement.
See below.

1574809438372.png


eT
 
Last edited:

Thread Starter

rovies

Joined Nov 26, 2019
15
Thanks you for all your suggestions. Let me see if I can clarify a bit more by supplying my whole schematic. You will see that there are no LED's in the drawing, I merely inserted them to see what was going on.
This is a Figuera Generator. All transistors (T1 - T8) are Darlington BDX53C. All resistors (R1 - R8) are 68 ohms
The sequence of the final pulsed output is shown in the second attachment.
I have put pull down resistorCD4017Drawing.pngSequencing.pngs on all unused inputs of the CD 4081.
 

Thread Starter

rovies

Joined Nov 26, 2019
15
From what I believe I can see - your reset from CD4017-2, pin 9 should go to BOTH resets. Otherwise when CD4017-2 goes into reset it remains in reset holding CD4017-1 in the reset mode. Until you clear CD4017-2 your chips won't run beyond that point.
Thanks Tonyr1084. This suggestion has made a difference. I just need to make sure that I am getting the required output from each of the 4017's. But so far so good
 

Thread Starter

rovies

Joined Nov 26, 2019
15
Thanks again eetech00. I do appreciate the time that it must have taken to (first) understand what I was trying to convey, and (second) draw the diagram.
 

Thread Starter

rovies

Joined Nov 26, 2019
15
Thanks Tonyr1084. This suggestion has made a difference. I just need to make sure that I am getting the required output from each of the 4017's. But so far so good
Hi Tonyr1084. I connected both resets to pin 9 of CD4017-2. Your logic made sense to me.
However, now if I connected an LED to all (16) of the individual outputs of each CD4017, before combining them, the LED on pin 3 of CD4017-1 does not light up.
 

Thread Starter

rovies

Joined Nov 26, 2019
15
Hi Tonyr1084. I connected both resets to pin 9 of CD4017-2. Your logic made sense to me.
However, now if I connected an LED to all (16) of the individual outputs of each CD4017, before combining them, the LED on pin 3 of CD4017-1 does not light up.
Sorry "connected" should be "connect"
 

Tonyr1084

Joined Sep 24, 2015
3,942
Thanks you for all your suggestions. Let me see if I can clarify a bit more by supplying my whole schematic. You will see that there are no LED's in the drawing, I merely inserted them to see what was going on.
This is a Figuera Generator. All transistors (T1 - T8) are Darlington BDX53C. All resistors (R1 - R8) are 68 ohms
The sequence of the final pulsed output is shown in the second attachment.
I have put pull down resistorView attachment 193225View attachment 193226s on all unused inputs of the CD 4081.
Even more confused now. Still don't understand why you're pushing one output against another. After reading several more comments, are you NOT using LED's? From diagram #2 - are you trying to make an up-down counter? Really just not sure what you're trying to do. And if you're pushing one output against another and you're using LED's, are they multi color?
 

BobaMosfet

Joined Jul 1, 2009
892
Hi, I have built the attached circuit which works, except for one issue. If the outputs of each 4017 are connected to LED's they all light up, and that is fine.
The problem is that I have to connect outputs from each 4017 together, so that they light up in a predetermined sequence.
For example, the output from pin 3 on the first counter, must be connected to output 6 of the second counter. Other examples are pin 2 of the first counter must connect to pin 5 of the second, and pin 4 must combine with pin 1. This is shown on the schematic. (apologies it is drawn using Excel)
The connection of these pairs of wires all work, except for Pin 3 of the first 4017 with Pin 6 of the second. What happens when I connect these outputs is that all the led's stop blinking, except for the output from 4017 (1) which stays onView attachment 193125
I can't help thinking that the output of pin 3 of 4017 (1) is being messed up by the reset signal of pin 15 on 4017 (2)
Any help on how to overcome this will be greatly appreciated
My God Man!!! That may be the most brilliant use of Excel in electronics that I've ever seen! That is outrageously good and _THANK YOU_ for the effort :)

Having said that, can you tell us simply, in two (2) sentences, what you're trying to accomplish. What you've done isn't wired right. These are counters, that you cascade. Clock is same for both simultaneous and driven from one source so they increment at the same time.

Not sure what you're trying to do.
 
Last edited:
Top