Remember, the pot value is 250k, that is its value when it is rotated fully for maximum resistance.
Your calculation should consider the pot value at mid position so you can adjust the timing.
To determine the timing range:
100k+1ohm (1 ohm=pot at minimum value) will set the minimum time =
1.1*(100k*1ohm)*2.2uF=0.242 sec.
100k+250k will set the maximum time =
1.1*(100k*250k)*2.2uF= 0.847 sec
100k+125k (125k=pot at mid position) will set the nominal time =
1.1*(100k*125k)*2.2uF= 0.545 sec
Good advice. I had after I posted did the calculation with a 500k and saw the difference was just about a 1/2 second longer so I did increase the pot to 500k.
Thank you.
They are voltage sensitive devices however, so its important that the input voltage transitions past 70% of the supply voltage for it to be recognized as a high state and 30% to be recognized as a low state.