Ohm's Law Simulator (V = IR)
Change voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change.
Drag the voltage or resistance sliders. Bigger voltage pushes more current, bigger resistance (more impurities in the resistor) lets less current through. The letters of V = I R grow and shrink with their values.
About the Ohm's Law Simulator (V = IR)
Free ohm's law simulator (v = ir). Change voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change. Drag, change the sliders and see the result live. No sign-up, works on phone and computer. Built for physics, the ohm's law simulator (v = ir) runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Change voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change. Use it to explore physics ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Ohm's Law Simulator (V = IR)
- Use the controls to change Voltage, Resistance. The simulation reacts instantly.
- Pick an option such as Numbers, Hide numbers to switch modes or load an example.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Double the voltage and read the current.
- Double the resistance and see what happens.
- Find a setting that makes the bulb very bright.
Key ideas you can learn
- V = I × R, so I = V ÷ R.
- Doubling the voltage doubles the current.
- Doubling the resistance halves the current.
- Power P = V × I makes the bulb glow.
Where this is used in the real world
All electronic devices are designed with Ohm's law: it sets the resistor in every LED light, charger and radio.
Who is this simulation for?
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. It works well for flipped classrooms because students can explore before the lesson.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
What is Ohm's law?
The current through a resistor is proportional to the voltage across it: V = IR.
How do I find current?
Divide the voltage by the resistance.
Is the Ohm's Law Simulator (V = IR) free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Ohm's Law Simulator (V = IR) work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.