Ohm's Law
V = I × R
Quick answer
This calculator solves V = I × R for Voltage. With Current 2 A, Resistance 0.47 kΩ, the result is 0.94 kV. It solves in 3 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
Ohm's Law is the foundational relationship in electronics, first published by Georg Simon Ohm in 1827. It states that the voltage across a conductor is directly proportional to the current flowing through it, with the constant of proportionality being the resistance. This linear relationship holds for ohmic materials like metals and carbon resistors at constant temperature, but breaks down for semiconductors, diodes, and other nonlinear devices. It is the starting point for nearly every circuit analysis technique including Kirchhoff's laws, nodal analysis, and mesh analysis.
Variables
- V — Voltage in volts (V), the electrical potential difference
- I — Current in amperes (A), the flow of electric charge
- R — Resistance in ohms (Ω), opposition to current flow
Practical Notes
Resistance increases with temperature for most conductors. For precise work, account for the temperature coefficient of the resistor material. Ohm's Law applies to DC circuits directly and to AC circuits when using complex impedance in place of resistance.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| V | Voltage | V | pV, nV, µV, mV, V, kV |
| I | Current | A | pA, nA, µA, mA, A, kA |
| R | Resistance | Ω | mΩ, Ω, kΩ, MΩ |
Step by step
- 1. What you know: Current 2 A, Resistance 0.47 kΩ
- 2. The relation: V = I × R
- 3. Substitute: I = 2 A, R = 0.47 kΩ
- 4. Result: Voltage = 0.94 kV
Related quantities from the same inputs
- P = V × I = 1.88 kW
Worked examples
Minimum range
Given: Current 2 mA, Resistance 1 Ω
Result: Voltage = 2 mV
Low range
Given: Current 20 mA, Resistance 10 Ω
Result: Voltage = 0.2 V
Typical
Given: Current 2 A, Resistance 0.47 kΩ
Result: Voltage = 0.94 kV
High range
Given: Current 100 A, Resistance 4.7 kΩ
Result: Voltage = 470 kV
Maximum range
Given: Current 1 kA, Resistance 47 kΩ
Result: Voltage = 47000 kV
Solving for each variable
Solve for Voltage
Current 2 mA, Resistance 1 Ω → 2 mV
Solve for Current
Voltage 0.33 V, Resistance 1 Ω → 0.33 A
Solve for Resistance
Voltage 0.33 V, Current 2 mA → 0.165 kΩ
How Voltage changes with Current
| Current (input) | Voltage (result) |
|---|---|
| 0.2 A | 94 V |
| 0.5 A | 0.235 kV |
| 1 A | 0.47 kV |
| 1.5 A | 0.705 kV |
| 2 A | 0.94 kV |
| 3 A | 1.41 kV |
| 4 A | 1.88 kV |
| 8 A | 3.76 kV |
| 14 A | 6.58 kV |
| 20 A | 9.4 kV |
The same result in other units
| Unit | Value |
|---|---|
| mV | 940000 |
| V | 940 |
| kV | 0.94 |
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<p><a href="https://vbatpower.com/formulas/ohms-law/">Ohm's Law</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Ohm's Law?
Use V = I × R. With Current 2 A, Resistance 0.47 kΩ, Voltage works out to 0.94 kV.
What is the formula for Ohm's Law?
The formula is V = I × R. Ohm's Law is the foundational relationship in electronics, first published by Georg Simon Ohm in 1827.
How do you find Current when you know the other values?
Rearrange for Current: with Voltage 0.33 V, Resistance 1 Ω, Current is 0.33 A.
How do you find Resistance when you know the other values?
Rearrange for Resistance: with Voltage 0.33 V, Current 2 mA, Resistance is 0.165 kΩ.
What units does Ohm's Law use?
Voltage is shown in mV, V, kV. Values are held in SI base units internally, so you can mix prefixes without converting by hand.
Related Concepts
All Basic Electronics formulas →Need more features?
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