shaneshane1
New Member
Hi im new to this whole time constant thing,i usually just ask for the answer, lol, but im at the stage were i should be working it out myself.
calculating how long it takes for a capacitor to reach 2/3 full
RC time constant = R X C (resistance x capacitor)
resistor = 68K (68,000 ohms)
capacitor = 470uF (0.000470 farads)
so the answer im getting = 31.96 (so 32 seconds)
so i put this to practice using approximatly 7V and timed it up to 32 seconds and the voltage was around 4.2V everytime and thats approximatly 2/3 of 7V
is this correct?????? and if so, how would i go about using that as a time delay to turn on a LED, so the LED comes on at approximatly 4.2V (32 seconds) what other components would i need?
calculating how long it takes for a capacitor to reach 2/3 full
RC time constant = R X C (resistance x capacitor)
resistor = 68K (68,000 ohms)
capacitor = 470uF (0.000470 farads)
so the answer im getting = 31.96 (so 32 seconds)
so i put this to practice using approximatly 7V and timed it up to 32 seconds and the voltage was around 4.2V everytime and thats approximatly 2/3 of 7V
is this correct?????? and if so, how would i go about using that as a time delay to turn on a LED, so the LED comes on at approximatly 4.2V (32 seconds) what other components would i need?