I need help on a circuit i am building. It is a manual sequencer with 4017 counter IC built into it. I am planning on increasing the current and voltage flowing through output pins 1-7 and 9-11. i am also having trouble switching the pins coz because the pins switch at random each time i connect pin 4 to the ground. I know little of electronics and I would apprciate much if your replies come with schematics of parts i may need to add to my circuit.

 

You can use transistors,triacs or relays for increasing the voltage and current. But you will need to find the maximum load current and the voltage you are going to use in order to choose the best component for the application . You will need the datasheet http://www.national.com/ds/CD/CD4017BC.pdf of the 4017 to find the exact output pin arrangment if you need to light them accordingly since this IC outputs are not placed in order, I don't know why.

 

We need a schematic of what you are trying to do. I have several examples of sequencers in my article LEDs, 555s, Flashers, and Light Chasers, it might give a hint.

 

There is something called "switch bounce". Every time you make or break a switch contact you will get multiple pulses.

 

Well, it is not guaranteed, but there is a good chance. It is easy to beat though.

 

it almost took forever for me to reply to this forum. thanks for your replies. the debouncer (i used 555 timer ic now) solved one of my problems with the circuit im building, but there's another problem that i need help on. The 4017 (or im suspecting the capacitive-resistive circuit maybe??) is quite erratic. In several trigger trials i have done, there are times that the 4017 doesnt start at pin 3, it sometimes start instantly at pin 4. Pls help me on this. The relays/transistors will be added later for high rated bulbs....Attached is the schematic ...

 

That's a terrible circuit. There are more things wrong than right with it. Use one of Bill's sequencer schematics.
http://forum.allaboutcircuits.com/blog.php?bt=684

 

That's a terrible circuit. There are more things wrong than right with it. Use one of Bill's sequencer schematics.
http://forum.allaboutcircuits.com/blog.php?bt=684

I will try Mr. Bill's Circuit and expand it. I just hope these errors will not manifest to my intended application of the circuit later. Thanks KJ6EAD.

 

I tried Mr. Marsden's sequencer and a similar project of Mr. Bowden http://www.bowdenshobbycircuits.info/4017-2.gif and I remain experiencing the same problem in several trials i have done....

i noticed also that in some of the trials, some of the Leds (three or more) light up consecutively, the moment the circuit is turned on..

I dont really understand what could be the cause of the erratic sequencing . Once again, i am very thankful for any advice on this...

 

There are a few possibilities for your problems. You're going to have to show your circuit, either a schematic of exactly what you have or better yet, a sharply-focused, well-lit photo.

 

4017's often start with multiple outputs high, or a random output high. This sorts itself out when it rolls over, but if you need to you can use a small electrolytic capacitor and resistor to pull the reset up for a bit on power up so it starts at zero every time.

 

4017's often start with multiple outputs high, or a random output high. This sorts itself out when it rolls over, but if you need to you can use a small electrolytic capacitor and resistor to pull the reset up for a bit on power up so it starts at zero every time.

This definitely solved my problem. Thanks very much Magnet18.

 

I guess I need to add that feature on several of my schematics, most cases it doesn't matter.

The other thing that occurs is lack of bypass capacitors, which is pretty much required in all electronics.

Decoupling or Bypass Capacitors, Why?