Explore the RC Circuit & Capacitor Simulator
Charge and discharge a capacitor through a resistor and watch voltage and current change. Free, no signup, runs in your browser.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The RC Circuit & Capacitor Simulator with sample data entered and the result showing.
What is the RC Circuit & Capacitor Simulator?
Charge and discharge a capacitor through a resistor and watch voltage and current change. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
RC circuits control timing in flash cameras, defibrillators, filters in audio equipment and the debounce circuits in every keyboard.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
The time constant is τ = R × C.
After one τ a charging capacitor reaches about 63% of the battery voltage.
While discharging, voltage and current both fall exponentially.
Click the switch to charge, then flip it to discharge.
Double the resistance. What happens to the charging time?
Find the moment the voltage reaches 63% and compare with RC.
Used for
Pick one to see how it fits.
Physics learners
Physics students in middle school, high school and first-year university, teachers who want a quick demonstration for the projector, and anyone revising for exams.
Try it freeTeachers
For teachers: project the RC Circuit & Capacitor Simulator on the board, let students predict the result, then run it together and test this: Double the resistance. What happens to the charging time?. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
What is the time constant of an RC circuit?
τ = R × C. It is the time for the capacitor to charge to about 63.2% of the supply voltage, or discharge to about 36.8% of its starting value.
Why does current start high when charging?
An empty capacitor acts like a wire, so the full battery voltage sits across the resistor and the current is V/R. As it charges, its voltage opposes the battery and the current falls.
Is the RC Circuit & Capacitor Simulator free to use?
Yes. The RC Circuit & Capacitor Simulator is free, needs no signup or download and runs in your web browser. It is part of the Physics group of AZRS simulations.
Does the RC Circuit & Capacitor Simulator work on a phone or tablet?
Yes. The RC Circuit & Capacitor Simulator takes touch input as well as mouse input, so you can use its 5 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
How do I use the RC Circuit & Capacitor Simulator?
1. In the RC Circuit & Capacitor Simulator, use the controls to change Battery voltage, Resistance, Capacitance, Time speed, Switch position. The simulation reacts instantly. 2. In the RC Circuit & Capacitor Simulator, pick an option such as Charge, Open, Discharge to switch modes or load an example. 3. In the RC Circuit & Capacitor Simulator, press "Empty the capacitor" to start, reset or change what is happening. 4. Start with this experiment: Click the switch to charge, then flip it to discharge. Drag any glowing handle, object or slider with your mouse or finger and the RC Circuit & Capacitor Simulator responds in real time. 5. Change one setting at a time and watch which readout moves, then compare it with this idea: The time constant is τ = R × C.
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Charge and discharge a capacitor through a resistor and watch voltage and current change. Free to use.
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