What is Ohm's Law?
At its core, Ohm's Law is the most fundamental equation in electronics. It describes how electric current flows through a resistance when a voltage is applied.
The formula is elegantly simple:
Where:
- V is Voltage (measured in Volts)
- I is Current (measured in Amperes)
- R is Resistance (measured in Ohms, Ω)
Visualize the Relationship
Think of electricity like water flowing through a pipe:
- Voltage is the water pressure pushing the water.
- Current is the actual flow rate of the water.
- Resistance is the pipe's narrowness (restricting flow).
If you increase the pressure (Voltage), the flow (Current) increases. If you squeeze the pipe (increase Resistance), the flow decreases.
Calculating Power
Beyond just V, I, and R, you often need to know how much work the electricity is doing—this is Power (measured in Watts).
Combining this with Ohm's Law gives us two other useful variations:
- $P = I^2 \times R$ (Great for finding heat loss in wires)
- $P = V^2 / R$
Try It Yourself
Calculating these values by hand is good practice, but for complex circuits or quick checking, a simulation is better.
Our Ultimate Ohm's Law Calculator lets you:
- Enter ANY two variables to find the rest.
- Visualize the circuit in real-time.
- See the wire heat up as power increases!
Launch the Circuit Simulator to test your knowledge now.