The running LED circuit using 555 & 4017 will withstand 10 outputs..
when we switch off the power supply the output remains same where it was actually end.. means if it ends with 7th output after switching ON it is starting from 8th output..

Any way of resetting the IC for every switch off?.. I need it to start from the first after every start up.. If any other IC do this work let me know..
Thanks.

 

0.1µF capacitor from RESET (15) to VDD (16), and a 10K resistor from RESET (15) to VSS (8).

When you power-up the capacitor momentarily acts as a short, pulling reset input high. This resets the counter to zero. The capacitor quickly charges through the resistor, pulling the reset input to ground, and allowing the counter to count. This reset pulse will last less than a millisecond.

Ken

__________________
"To invent, you need a good imagination and a pile of junk."
Thomas A. Edison (1847 - 1931)

 

Use a power up reset circuit to reset the counter to zero. The pulse must be the positive going edge of a pulse.

Use a 100n capacitor and a 10K resistor as shown in the schematic.

At power up the capacitor produces a short positive pulse while charging. This resets the counter. After power is established the MR-pin will just "see" GND.

 

Hi Ken,

sorry for the paralleling reply on that. I was busy drawing the schematic while you already posted your reply. However both suggestions are the same.

Take care and kind regards

Hans

 

Thanks for replies.. will try it now..
So can i use this as a password circuit?..
Example by pressing push button 1(initial clk) i can get the first output.. so i am planing to give first output to next pushbutton 2(+ive clk), so i can get the second output... if i put the relay there it will ON only after pressing 1&2 right?.

This is my guessing.. will it work?.

 

The contacts on a pushbutton "bounce' many times when the pushbutton is pushed. The counter will count them all instead of having just a single clock pulse. So you need to use a "de-bounce" circuit for the clock input.

Your idea of a password is too simple. You can press any pushbutton twice or any two pushbuttons in sequence to have the counter count to 2.

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Uncle $crooge

 

yes... understood. i was wrong.. I can make it using 4 555 in monostable mode.. the problem is i am getting lots of false triggering... when i switch ON some other lights its getting triggered even having stray capacitance.. Any perfect password circuit available?..