Power Calculation Formula In AC Circuit

AC Real Power Formula:

\[ P = V \times I \times \cos \phi \]

Real Power (P):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What Is AC Real Power?

Real power (P) in AC circuits represents the actual power consumed by resistive loads and converted into useful work. Unlike apparent power, real power accounts for the phase difference between voltage and current through the power factor.

2. How Does The Calculator Work?

The calculator uses the AC real power formula:

\[ P = V \times I \times \cos \phi \]

Where:

\( P \) — Real power (Watts)
\( V \) — RMS voltage (Volts)
\( I \) — RMS current (Amperes)
\( \cos \phi \) — Power factor (dimensionless, 0-1)

Explanation: The formula calculates the actual power consumed in an AC circuit, taking into account the phase relationship between voltage and current through the power factor.

3. Importance Of Power Factor

Details: Power factor indicates how effectively electrical power is being used. A low power factor means poor utilization of electrical power, resulting in higher energy costs and inefficient system operation.

4. Using The Calculator

Tips: Enter RMS voltage in volts, RMS current in amperes, and power factor (between 0 and 1). All values must be positive, with power factor ranging from 0 to 1 inclusive.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between real power and apparent power?
A: Real power (P) is the actual power consumed and converted to work, while apparent power (S) is the product of voltage and current without considering power factor.

Q2: What is a good power factor value?
A: Typically, power factors above 0.95 are considered good. Values below 0.85 may result in utility penalties for commercial users.

Q3: How can power factor be improved?
A: Power factor can be improved by adding capacitors to the circuit (power factor correction) or by reducing inductive loads.

Q4: What causes low power factor?
A: Low power factor is primarily caused by inductive loads like motors, transformers, and fluorescent lighting that cause current to lag behind voltage.

Q5: Is power factor always between 0 and 1?
A: Yes, power factor ranges from 0 to 1, where 1 represents perfect efficiency (purely resistive load) and 0 represents purely reactive load with no real power consumption.