Mr Calcu | Easily solve for voltage, current, or resistance—perfect for students, engineers, and makers who want fast, accurate answers.
Quickly compute voltage, current, or resistance using Ohm's Law. Master electronics with this powerful, easy-to-use tool that boosts confidence and clarity.
Ohm's Law Calculator Description
Ohm's Law: Understanding the Basics
Ohm's Law is a cornerstone of electrical engineering, describing how voltage, current, and resistance relate to each other in a circuit.
Core Formula
I = V / R
- I — Current (Amperes, A)
- V — Voltage (Volts, V)
- R — Resistance (Ohms, Ω)
Alternative Forms
V = I × R
R = V / I
Pro Tip: If you're designing for high-current systems, keep resistance low to avoid energy loss and overheating.
Important Considerations
Where Ohm's Law Applies
- Linear (ohmic) components: resistors, wires
- DC and low-frequency AC circuits
Where It Does Not Apply
- Non-ohmic components: diodes, transistors
- High-frequency systems with significant inductance/capacitance
- Circuits where temperature significantly alters resistance
Real-World Examples
Smartphone Charging Circuit
- Voltage = 5V
- Current = 2A
- Resistance = V / I = 2.5Ω
Electric Vehicle Power Delivery
- Voltage = 400V
- Current = 100A
- Resistance = V / I = 4Ω
Special Cases
- Open Circuit: R → ∞ → I = 0
- Short Circuit: R → 0 → I = V / R → Very large (potentially dangerous)
- Zero Voltage: V = 0 → I = 0 (if R ≠ 0)
- Extreme Low Resistance: Risk of thermal damage or fire
- Temperature Rise: Increases R → Decreases I over time
Take control of your circuits—start calculating with confidence now!