Ohm's Law Calculator (V = IR)
Ohm's Law Calculator
Ohm's Law is one of the most fundamental principles in electrical engineering. It defines the relationship between voltage (V), current (I), and resistance (R) in a circuit.
Conversion Formula
V = I × R means voltage equals current multiplied by resistance. Rearranging: I = V/R and R = V/I.
Step-by-Step Examples
V=12V, I=2A = R=6Ω
R = 12 / 2 = 6 ohms
I=0.5A, R=100Ω = V=50V
V = 0.5 × 100 = 50 volts
V=9V, R=3Ω = I=3A
I = 9 / 3 = 3 amps
History
Georg Simon Ohm published his law in 1827 in "Die galvanische Kette, mathematisch bearbeitet." It was initially met with skepticism but is now a cornerstone of electrical engineering.
Common Use Cases
- Circuit design
- Troubleshooting electrical faults
- Sizing wires and fuses
- LED resistor selection
- Battery and power supply design
Frequently Asked Questions
What is Ohm's Law?
Ohm's Law states that voltage equals current times resistance (V = IR). It describes the relationship between voltage, current, and resistance in an electrical circuit.
How do I use the Ohm's Law calculator?
Enter any two of the three values (voltage, current, resistance) and the calculator will compute the missing value.
What units does Ohm's Law use?
Voltage is measured in volts (V), current in amperes (A), and resistance in ohms (Ω).
Who discovered Ohm's Law?
Georg Simon Ohm, a German physicist, published the law in 1827 after extensive experimentation with electrical circuits.
Does Ohm's Law apply to all circuits?
Ohm's Law applies to linear (ohmic) components like resistors. Non-linear components like diodes and transistors do not follow Ohm's Law exactly.
What happens if resistance is zero?
If resistance is zero, theoretically infinite current would flow (a short circuit). In practice, every conductor has some resistance.
How is Ohm's Law used in everyday life?
It is used to design circuits, size wires, select fuses, and troubleshoot electrical problems in homes and vehicles.