Electrical Power Calculator
Calculate electrical power using voltage, current, resistance, and power factor for DC and AC circuits
Calculate Electrical Power
Electric potential difference across the circuit
Electric current flow through the circuit
Select desired unit for power output
Electrical Power Results
Power Analysis
Example Calculation
Household Device Example
Device: Electric kettle (AC)
Voltage: 120 V (household outlet)
Current: 10 A
Power Factor: 1.0 (resistive load)
Calculation
P = V × I × pf
P = 120 V × 10 A × 1.0
P = 1200 W (1.2 kW)
Power Formulas
P = V × I
Basic power formula
For DC circuits or AC with power factor
P = V²/R
Power from voltage and resistance
Useful for resistive loads
P = I² × R
Power from current and resistance
Joule heating formula
Typical Power Factors
Understanding Electrical Power
What is Electrical Power?
Electrical power is the rate at which electrical energy is transferred by an electric circuit. It represents the amount of work performed in a unit of time and is measured in watts (W). Power determines how much energy an electrical device consumes or produces.
DC vs AC Circuits
- •DC Circuits: Power = V × I (constant values)
- •AC Circuits: Power = V × I × pf (includes power factor)
- •AC values are typically RMS (root mean square)
Power Factor Explained
In AC circuits, the power factor (pf) represents how efficiently electrical power is being used. It ranges from 0 to 1, where 1 indicates perfect efficiency (resistive loads) and lower values indicate reactive components that reduce efficiency.
P = V × I × cos(φ)
where φ is the phase angle between voltage and current
Joule's Law
P = I² × R describes the power dissipated as heat in a resistor. This is fundamental for understanding power loss and heating effects in electrical circuits.
Ohm's Law Relationship
Combined with Ohm's law (V = I × R), the power formulas P = V²/R and P = I² × R provide multiple ways to calculate power depending on known values.
Energy and Power
Energy (in kWh) = Power (in kW) × Time (in hours). This relationship is crucial for calculating electricity consumption and costs.