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Ohm's law calculator: Calculate voltage, current, resistance and power. The basis of electrical engineering.
Fill in the fields below and click "Calculate".
Ohm's law calculator: Calculate voltage, current, resistance and power. The basis of electrical engineering.
Fill in the fields below and click "Calculate".
Ohm's law: calculating voltage, current and resistance
Ohm's law is the basis of electrical engineering. Our calculator enables quick calculations for:
- Circuit design: Dimensioning resistors for LED circuits
- Troubleshooting: diagnosing electrical problems
- Electrical engineering training: Practical application of formulas
- DIY electronics: Build hobby circuits safely
- Power calculation: Determine P = U × I or P = I² × R
The four basic formulas:
- U = R × I (voltage = resistance × current)
- I = U / R (current = voltage / resistance)
- R = U / I (resistance = voltage / current)
- P = U × I (power = voltage × current)
Practical example: One LED (20 mA, 2V) on 12V supply. Required series resistor: R = (12V - 2V) / 0.02A = 500 Ω. Power: P = 10V × 0.02A = 0.2W. Select a 510 Ω resistor with a load capacity of at least 0.25W. Ohm's law applies to ohmic resistors at constant temperature.
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