1. Ohm's Law and Power Formulas

The fundamental relationships between voltage (V), current (I), resistance (R), and power (P) in electrical circuits are described by these formulas:

2. How the Calculator Works

The calculator uses the interrelationships between these four variables. You only need to provide any two known values, and it will calculate the other two.

Key Formulas Used:

• When you know voltage and current: \( P = V \times I \), \( R = \frac{V}{I} \)
• When you know voltage and resistance: \( I = \frac{V}{R} \), \( P = \frac{V^2}{R} \)
• When you know current and resistance: \( V = I \times R \), \( P = I^2 \times R \)

3. Practical Applications

Details: These calculations are essential for circuit design, electrical safety, component selection, and power management in both AC and DC systems.

4. Using the Calculator

Tips: Enter any two known values (voltage, current, resistance, or power) and the calculator will compute the other two. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between AC and DC in these calculations?
A: For resistive loads, the formulas work the same. For reactive loads in AC, you need to consider power factor and impedance.

Q2: How do I calculate power in three-phase systems?
A: For balanced three-phase: \( P = \sqrt{3} \times V_{line} \times I_{line} \times \text{pf} \)

Q3: Why does resistance affect power?
A: Resistance converts electrical energy into heat. Higher resistance with same current means more power dissipated as heat.

Q4: What's the relationship between watts and volt-amps?
A: Watts (W) are real power, volt-amps (VA) are apparent power. They're equal in purely resistive circuits.

Q5: How accurate are these calculations?
A: Perfectly accurate for ideal resistors. Real-world components may have additional factors like temperature dependence.