Charging and discharging a capacitor
Charging and discharging a capacitor is an interactive experiment in Electronic Components, a free simulation from StudyFi Lab that runs right in your browser.
A capacitor does not charge instantly through a resistor: its voltage rises as u_C = U·(1 − e^(−t/τ)) while the current falls off. The time constant τ = R·C sets the pace — after one τ the capacitor reaches 63 % of the source voltage, and when discharging it drops to 37 %. After about 5τ the process is practically over.
Try this: Let the capacitor charge, then switch to discharge. Double R (10 kΩ → 20 kΩ) and check that τ and the whole process take twice as long.
Frequently asked questions
What does the “Charging and discharging a capacitor” experiment show?
A capacitor does not charge instantly through a resistor: its voltage rises as u_C = U·(1 − e^(−t/τ)) while the current falls off. The time constant τ = R·C sets the pace — after one τ the capacitor reaches 63 % of the source voltage, and when discharging it drops to 37 %. After about 5τ the process is practically over.
How do I try “Charging and discharging a capacitor”?
Let the capacitor charge, then switch to discharge. Double R (10 kΩ → 20 kΩ) and check that τ and the whole process take twice as long.
Studying for a test?
Upload your notes and StudyFi turns them into flashcards, tests and podcasts.