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Help w/4017 decade counter

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Help w/4017 decade counter

Postby kjones6039 » Fri Apr 22, 2011 2:53 am

I want to use a 4017 CMOS decade counter, triggered by a 555 timer, to turn on 4-5 lights in sequence and then stop, leaving the lights on until I perform a hardware reset.

I have no problem with this circuit except I am not sure how to halt the count at the proper time.

Any help will be appreciated.

Ken
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Postby pebe » Fri Apr 22, 2011 10:15 am

I assume you are clocking with the +ve pulses from the 555 applied to the 4017 CLK, pin 14, while CE, pin 13, is held low.

If you connect CE to output 5, pin1, then as soon as count 5 is reached CE will be taken high and inhibit any further count.

BTW, you said 'lights' (plural). But the 4017 will only output one pin high at a time so you can only get one LED on at a time.
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Postby kjones6039 » Fri Apr 22, 2011 2:55 pm

Thanks for the reply. That clears it up for me!

I assume you are clocking with the +ve pulses from the 555 applied to the 4017 CLK, pin 14, while CE, pin 13, is held low.


Correct

BTW, you said 'lights' (plural). But the 4017 will only output one pin high at a time so you can only get one LED on at a time.


I actually did understand that. I may/may not want to keep them all on, in which case I might consider a latch to hold them on, pending a hardware reset.

Thanks again!

Ken
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Postby steveo » Sun Jun 12, 2011 4:48 am

Hello,
If you want to turn on the LED on different counts. You can connect the led to several output pins if you use a diode between each pin and the LED.
By using the diodes you can program several LEDs to the same pins
Just be sure you have enough drive for more than one diode.

Take care,
Steve O.
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