About AC Power Calculations and the Power Triangle
Power in AC circuits is divided into "Active Power" (the actual power consumed to perform work) and "Reactive Power" (power that merely flows back and forth between the power source and the load) depending on the phase difference between voltage and current. The combined total of these is called "Apparent Power."
Based on fundamental principles of electrical engineering, this calculator utilizes complex power concepts to perform accurate vector math. It provides reliable figures for a wide range of applications, including theory coursework, licensing exams, and practical power factor correction capacitor sizing.
Explanation of Key Parameters
- Active Power (P): The actual power consumed by resistive components. Unit: W (watts).
- Reactive Power (Q): Energy stored temporarily in inductors or capacitors. Unit: var (volt-amperes reactive). Lagging power (inductive) is handled as positive, while leading power (capacitive) is handled as negative.
- Apparent Power (S): The total power supplied by the source. Unit: VA (volt-amperes).
- Power Factor (cosθ): The ratio of apparent power that is used as active power. It serves as an indicator of electrical energy efficiency.
How to Use
- Enter at least two known values for the parameters you want to calculate.
- Valid combinations include Voltage and Current, or a mix of Power components (P, Q, S).
- Click the "Calculate" button to compute all remaining missing values and draw the corresponding vector diagram on the right.
Frequently Asked Questions (FAQ)
A. It appears when the values entered violate the laws of physics. For example, Active Power (P) being greater than Apparent Power (S) is theoretically impossible (P > S) and will trigger an error. It also appears if there are fewer than two input fields filled.
A. Yes, it is perfect for understanding the power triangle and double-checking your answers on practice problems. Visualizing the vector diagram lets you intuitively grasp the impact of phase differences.
A. This tool is configured for single-phase AC. For 3-phase AC circuits, you will need to apply phase-specific voltages and currents, or manually adjust the results by multiplying by √3 depending on your circuit setup.
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