cascaded 4017s


Joined Feb 19, 2009
A 9,999 second egg timer?

No values of resistor or cap on NAND based oscillator.

No reset button, though. You always need a reset button. People have a sort of fundamental need to have a reset button available, even if they never use it.


Joined Jul 17, 2007
R2 is too low of a value to ensure that the output of the clock NAND can rise high enough to trip it's own Schmitt trigger input. R2 should be increased to at least 3.9k.

Place a 10k resistor between the RES line and the output of the lowest NAND gate's output. That way you can add a N.O. pushbutton switch that momentarily connects the RES inputs to +12v.

Thread Starter


Joined Oct 26, 2011
yes actually checking over the schematic r2 should be marked as 10k,some one has eaten the "0" far as the reset goes the customer who im building this for has given me how he wants it designed with the reset as is,but it is very easy to change things around and add an external reset if needed.This is a controller for flashing lights,one of 10.Already have a driver designed for the lighting side
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