1. What is the Power Equation?

The power equation (W = V²/R) calculates electrical power in watts from voltage and resistance. It's derived from combining Ohm's Law (V = IR) with the basic power formula (P = IV).

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

• \( W \) — Power in watts (W)
• \( V \) — Voltage in volts (V)
• \( R \) — Resistance in ohms (Ω)

Explanation: The equation shows that power increases with the square of voltage and decreases with higher resistance.

3. Importance of Power Calculation

Details: Calculating power is essential for circuit design, component selection, and ensuring electrical systems operate within safe limits.

4. Using the Calculator

Tips: Enter voltage in volts and resistance in ohms. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What if I know current instead of voltage?
A: Use P = I²R or P = IV if you know current (I) and either resistance or voltage.

Q2: Does this work for AC circuits?
A: For AC, you need to use RMS voltage values and consider power factor for reactive loads.

Q3: What are typical power ratings for household items?
A: Light bulbs: 5-100W, TVs: 50-400W, Microwaves: 600-1200W, Toasters: 800-1500W.

Q4: How does resistance affect power?
A: For a fixed voltage, higher resistance means lower power. For a fixed current, higher resistance means higher power.

Q5: What's the relationship between watts and heat?
A: All power dissipated in a resistor is converted to heat, so higher watts means more heat generated.