Hi Gut,
A capacitor charges through a resistor to 63% of the supply voltage in a time period that equals R times C, where R is in ohms and C is in Farads. So a 1uF capacitor will charge through a 10K resistor to 63% of the supply voltage in 10ms. You could also use a 10uF cap and a 1k resistor, a 100uF cap and a 100 ohm resistor etc.
It might be easier to detect when a charging capacitor's voltage reaches exactly one-half of the supply voltage. It occurs in a time period that equals 0.71 times R times C.
So a 1uF cap will charge through a 14.1k resistor to half the supply voltage in 10ms.
Don't ask me for the formula. I never use it since it is worn off in my old book. I just use the graph in the book that is still clearly visible. :lol: