4017 Decade Counter/Divider with 10 Decoded Output

Discussion in 'Homework Help' started by hackman, Oct 13, 2005.

  1. hackman

    Thread Starter New Member

    Oct 13, 2005

    I'm trying to design a circuit that enables a buzzer for 8 seconds, turns it off and then turns on an LED for 5 seconds, and then shuts down.

    I'm after this information... what does a 4017 Johnson Counter/Decade Counter/Divider with 10 Decoded Outputs do, and if I connect two 555 timers in series with Pin 2 of the IC 4017, should it give me the desired output?

    Button push & release ----> Buzzer ON (8s) ----> Buzzer OFF ----> LED ON (5s) ----> LED OFF.

    4017's Pin 2 ----> 555 (#1) ----> Buzzer ----> 555 (#2) ----> LED.

    Help/alternate ideas would be much appreciated.

  2. viterbi

    New Member

    Oct 13, 2005
    Check out these websites: http://www.doctronics.co.uk/4017.htm or http://www.play-hookey.com/digital/johnson_counter.html and http://www.standardics.philips.com/products/counters/4017/

  3. Sebi

    Well-Known Member

    Sep 24, 2005
    What accuracy needed? If the 5sec can be 6 sec, two chips do the job: 4011 and 4017. Two gates of 4011 formed a 0,5Hz time-base oscillator for 4017, another two work as R-S flip-flop for start-stop. The first four outputs of 4017 go to buzzer driver with diodes (OR-gate), the next three go to LED with diodes. 8. output wired to reset of flip-flop.
    In this case: pushbutton set the FF, start counter with 0,5Hz so the buzzer ON for 8sec...buzzer OFF and LED ON for 6sec...reset and stop.
  4. beenthere

    Retired Moderator

    Apr 20, 2004

    A Johnson, or ring counter, has only one of its 10 outputs active as it counts. This is different from a decade or BCD counter that has multiple outputs active such that they can be interpreted as tha equivalent of the value in the counter.

    A ring counter goes back a long way in electronics to vacuum tubes. They were first used in lab equipment for event counters, and drove Dekatron tube indicators. Later, they enabled Nixie tube cathodes, of ran those horrible neon H-P decade indicators.