WORKBENCH 02 / 4 min TO EXPLORE
Ohm’s Law Calculator
Explore the relationship between voltage, current, and resistance. Change a value. See why.
- 01 Try an example
- 02 Change one thing
- 03 Understand why
Try it out
A 9 V supply across a 1 kΩ resistor produces 9 mA of current.
Results update as you type. Try changing just one value.
SEE YOUR CIRCUIT
THE IDEA BEHIND THE NUMBERS
Three quantities. One relationship.
Voltage is the electrical potential difference across a component. Current is the rate of electric charge flow. Resistance describes how strongly a component opposes that flow.
The formulas use volts (V), amperes (A), and ohms (Ω). The calculator converts milliamps and kilohms for you. Power is calculated with P = V × I, in watts.
A quick guide to the units
- V
- Volts measure voltage: the electrical potential difference.
- A / mA
- Amps measure current. 1 A = 1,000 mA.
- Ω / kΩ
- Ohms measure resistance. 1 kΩ = 1,000 Ω.
- W
- Watts measure power. In a resistor, this power becomes heat.
What happens if you change something?
Keep resistance fixed and double the voltage: current doubles. Keep voltage fixed and double the resistance: current halves. This model describes an ideal resistor; LEDs and other nonlinear components need a different model.