1. What is the Power Equation?

The power equation (P = V × I) calculates electrical power in watts from voltage (V) and current (I). It's fundamental for understanding transformer performance between 110V and 220V systems.

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

• \( P \) — Power in watts
• \( V \) — Voltage in volts
• \( I \) — Current in amperes

Explanation: The equation shows the direct relationship between voltage and current in determining electrical power.

3. Importance of Power Calculation

Details: Accurate power calculation is crucial for transformer sizing, circuit design, and ensuring electrical safety when converting between 110V and 220V systems.

4. Using the Calculator

Tips: Enter voltage in volts and current in amps. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How does this apply to 110V/220V transformers?
A: The same power equation applies, but remember that stepping up voltage reduces current and vice versa while maintaining power (minus small losses).

Q2: What's the difference between apparent power and real power?
A: This calculator shows real power (watts). For AC systems with reactive loads, apparent power (VA) includes a power factor component.

Q3: Can I use this for DC and AC systems?
A: Yes, for DC and AC resistive loads. For AC inductive/capacitive loads, power factor must be considered.

Q4: How do I calculate current if I know power and voltage?
A: Rearrange the equation: I = P / V. For example, a 100W device at 220V draws about 0.45A.

Q5: Why is power calculation important for transformers?
A: Transformers must be sized to handle the required power (in watts or VA) to prevent overheating and ensure proper operation.