Calculation of electrical quantities
⚡ Electrician's Calculator: Ohm's Law, Power and Current
Our tool replaces reference books and manual calculations. It allows you to instantly find an unknown circuit parameter, knowing the other two. This is the basis needed both for checking your physics homework and for actually installing wiring.
- Ohm's Law:Find voltage (U), current (I) or resistance (R).
- Power calculation: Basic formula P = U × I. If you need an in-depth calculation for selecting equipment, use our separate power calculator.
- Energy and charge:Calculation of consumption (Joules/kWh) and electric charge (Coulombs).
🔥 Practical usage examples
Why is this needed in life, and not just in a textbook?
- Choosing a circuit breaker: You know the power of the boiler (for example, 2 kW) and the network voltage (220 V). Use the formula I = P / Uto find out the current strength and select a machine.
- Industrial tasks: If you connect machines or pumps, conventional formulas may give errors due to inrush currents and cos φ. For such purposes, we have a specialized tool - calculation of three-phase electric motor power.
- Electricity consumption: To understand how much the device will “wind up” per day, use the energy calculation function (work × time).
Frequently asked questions (FAQ)
🔹 For what current are these formulas suitable (AC or DC)?
The basic calculator uses the classic Ohm's law, which is ideally accurate for direct current (DC) circuits and alternating current (AC) circuits with resistive loads (incandescent lamps, heaters, irons).
🔹 What are the input values measured in?
For the correct result, use the basic SI units: Volts (V), Amperes (A), Watts (W), Ohms (Ohm). If you have kilowatts (kW), multiply the value by 1000 before entering.
🔹 How to calculate power for 380 Volts?
For a three-phase network, the formula is more complicated: P = √3 × U × I × cosφ. For this we recommend using the link to calculation of three-phase power above on the page.
Need more tools? Go to general catalog of calculators.