Reply to "Semaphore and 555 Timer Circuit"

stan2004OGR Forum Member

The 4017 has a quirk where it can power up in an "illegal" state which probably explains the unusual LED combination you describe. As the datasheet says,

Automatic counter code correction is provided by an internal circuit: following any illegal

code the counter returns to a proper counting mode within 11 clock pulses.

So you can wait 11 pulses of the 555...or you can apply a power-on reset pulse as GRJ suggests to the reset pin of the 4017.

2/8/158:40 PM

<ul id="{%=id%}ButtonGroup" class="button-group h-popup-buttons even-button-group even-1">
    <li id="{%=id%}Okay_buttonContainer"><a id="{%=id%}Okay" href="javascript:void(0);" class="button success no-margin-bottom h-alert-modal-ok-button" role="button">OK</a><script type="text/javascript">
        (function() {
            function {%=id%}Okay_click(event, data) {
            {%=id%}Popup.hide();
        }
        
                $('#{%=id%}Okay').on('click', {%=id%}Okay_click);
        })();
    </script></li></ul><a href="javascript:void(0);" class="close-reveal-modal" aria-label="Close Modal">&#215;</a><div class="last-modal-focus focus-utility-element" tabindex="0"></div>
</div>
<script type="text/javascript">
        (function() {
            {%=id%}Popup = new SS.Popup.ModalPopup('{%=id%}');
        })();
    </script>

Skip to main content

Membership Required

Remove From Your Block List

Manage Follow Preferences

Block

OGR Forum Supporting Membership Required

OGR Forum Supporting Membership

Help support this forum with an OGR Forum Supporting Membership.You will be able to watch the videos in the INSTRUCTIONAL VIDEO FORUM!A one-year OGR Forum Supporting Membership is only $12 per year, so sign up now!

OR

Access the ALL the OGR VIDEO FORUMS AND over 300 back issues of OGRwith a DIGITAL SUBSCRIPTION!

Please wait...

Help support this forum with an OGR Forum Supporting Membership.
You will be able to watch the videos in the INSTRUCTIONAL VIDEO FORUM!
A one-year OGR Forum Supporting Membership is only $12 per year, so sign up now!

Access the ALL the OGR VIDEO FORUMS AND over 300 back issues of OGR
with a DIGITAL SUBSCRIPTION!