LED circuit

Discussion in 'General Electronics Chat' started by Khalid Abur-Rahman, May 6, 2009.

  1. Khalid Abur-Rahman

    Thread Starter Active Member

    Dec 25, 2008
    34
    0
    How do I wire an LED in sequence so that one switch turns them on one at a time?



    I want to be able to press the button once and one LED will turn on, when I press it again the second turns on, and again the third turns on, and finally when I press it a third time I would like them all to turn off.

    Is this possible and if so how can I accomplish it?

    Thanks for any and all responses
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    This should work.
     
  3. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    A single decade counter can do the job.

    Connect led1 to Q1, led2 to Q2, led3 to Q3 and Q4 to the reset input of the counter. Use a switch to pulse the counter as to count up. Note that you may need to debounce the switch if by one press the output of the counter moves more than one position.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Come again? That requires 8 input pulses to get back to zero. The LEDs will light up in a binary sequence.
    Did I misunderstand you? Or did I misunderstand the OP?

    My understanding of the OP's requirements are as follows:

    Code ( (Unknown Language)):
    1. 0 0 0
    2. 1 0 0
    3. 1 1 0
    4. 1 1 1
    5. 0 0 0
    6. etc.
    Maybe he wants a 4017-type sequence. I really don't think he wants a binary sequence.
     
  5. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    A decade counter does not output a binary value. It has outputs from Q0 to Q9 for example and it increments an output each time you clock it. If you connect Q4 to its reset input it will reset and start counting from Q0 when you clock it for 4 times. Thus, it does not require 10 pulses to cycle.

    Here is one:

    http://i151.photobucket.com/albums/s136/CharlesArney/Circutry/4017 IC/DecadeCounter1.jpg
     
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Sorry. There are two kinds of decade counters. I think of the 4017 as a 5-stage Johnson counter, but I know it is called a decade counter. When I think of a decade counter, i think of a modulo-10 binary counter like the 7490. I totally spaced out on the 4017 whe I criticized your post.:(
    I thought of it before I designed the circuit I posted, but concluded that wasn't what our OP wanted. I hope he comes back with clarification.
     
  7. Slider2732

    Member

    May 6, 2009
    17
    0
  8. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    RonH,

    Maybe you are right about the user specification. We will see when he comes back. ;)
     
  9. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
Loading...