I would like to understand the equation for discharging a capacitor in X seconds. I want it discharged when I say so (X).
Extra, but not the subject. I would also like to understand the equation for charging a capacitor in X seconds. I want it charged when I say so (X).
Can you please help?
Here's what I learned from MrAl in a previous thread a while back. But those do not teach me how to discharge, and charge a capacitor when I say so. So if I wanted it discharged or charged COMPLETELY in X seconds.. How would I do that?
Time to Charge a Capacitor #1 : Vc=Vs*(1-e^(-t/RC))
Vc = Capacitor voltage after time t.
t = Time in seconds.
Vs = Source voltage (like a battery).
R = Resistance in Ohm's
C = Capacitance in Farads.
e = The base of the natural log system. Aka Euler's number : 2.7182818284590452353602874713527.....
Time to Discharge a Capacitor #1 : Vc1=Vc0*(e^(-t/(R*C)))
Vc0 = Starting Voltage of the Capacitor
Vc1 = Ending Voltage after time t.
t = Time in seconds.
e = The base of the natural log system. Aka Euler's number : 2.7182818284590452353602874713527.....
R = Resistance in Ohm's
C = Capacitance in Farads.
So if I had a capacitance of 10uF (0.00001F), and a resistance of 100k (100,000 Ω).
So that's 0.00001F * 100,000Ω = 1 second.
Times 5, because in 5 time constants, it will either be fully charged, or discharged. Right? So it will take 5 seconds then to charge or discharge the 10uF capacitor with 100k resistor.
Let's make it five times less than, to get it to actually discharge in 1 second after 5 time constants.
0.00001F / 5t = 0.00002F (50uF)
100,000Ω / 5t = 200,00Ω (200kΩ)
It's still going to be 5 seconds.
Let's just change the resistance then.. Let's make the resistance 5 times less.
I'm keeping the Capacitance at 10uF (0.00001F).
100,000Ω / 5 = 20,000Ω (20kΩ)
t = RC
20,000Ω * 0.00001F = 0.2 BINGO !!!
And after 5 time constants.. 0.2 x 5t = 1
It will charge and discharge in 1 second.
C = 0.00001F (10uF)
R = 20,000Ω
Now, let's amplify that. Let's discharge it in 1h 1m 1s 1ms
Seconds in an hour : 3600
3600s + 1s + 0.001s = 3601.001s (1h, 1m, 1s, 1ms)
20,000Ω x 3601.001 = 72,020,020 Ω (72.020 MΩ)
Do they even exist..? lol.. I bet I could probably lower or raise the Capacitance.. to allow the resistance to be lowered..
Is there a simpler equation for doing this..?
Extra, but not the subject. I would also like to understand the equation for charging a capacitor in X seconds. I want it charged when I say so (X).
Can you please help?
Here's what I learned from MrAl in a previous thread a while back. But those do not teach me how to discharge, and charge a capacitor when I say so. So if I wanted it discharged or charged COMPLETELY in X seconds.. How would I do that?
Time to Charge a Capacitor #1 : Vc=Vs*(1-e^(-t/RC))
Vc = Capacitor voltage after time t.
t = Time in seconds.
Vs = Source voltage (like a battery).
R = Resistance in Ohm's
C = Capacitance in Farads.
e = The base of the natural log system. Aka Euler's number : 2.7182818284590452353602874713527.....
Time to Discharge a Capacitor #1 : Vc1=Vc0*(e^(-t/(R*C)))
Vc0 = Starting Voltage of the Capacitor
Vc1 = Ending Voltage after time t.
t = Time in seconds.
e = The base of the natural log system. Aka Euler's number : 2.7182818284590452353602874713527.....
R = Resistance in Ohm's
C = Capacitance in Farads.
So if I had a capacitance of 10uF (0.00001F), and a resistance of 100k (100,000 Ω).
So that's 0.00001F * 100,000Ω = 1 second.
Times 5, because in 5 time constants, it will either be fully charged, or discharged. Right? So it will take 5 seconds then to charge or discharge the 10uF capacitor with 100k resistor.
Let's make it five times less than, to get it to actually discharge in 1 second after 5 time constants.
0.00001F / 5t = 0.00002F (50uF)
100,000Ω / 5t = 200,00Ω (200kΩ)
It's still going to be 5 seconds.
Let's just change the resistance then.. Let's make the resistance 5 times less.
I'm keeping the Capacitance at 10uF (0.00001F).
100,000Ω / 5 = 20,000Ω (20kΩ)
t = RC
20,000Ω * 0.00001F = 0.2 BINGO !!!
And after 5 time constants.. 0.2 x 5t = 1
It will charge and discharge in 1 second.
C = 0.00001F (10uF)
R = 20,000Ω
Now, let's amplify that. Let's discharge it in 1h 1m 1s 1ms
Seconds in an hour : 3600
3600s + 1s + 0.001s = 3601.001s (1h, 1m, 1s, 1ms)
20,000Ω x 3601.001 = 72,020,020 Ω (72.020 MΩ)
Do they even exist..? lol.. I bet I could probably lower or raise the Capacitance.. to allow the resistance to be lowered..
Is there a simpler equation for doing this..?
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