1. What is Current from Power and Voltage?

The relationship between current, power, and voltage is fundamental in electrical engineering. Current (I) can be calculated from power (P) and voltage (V) using the formula I = P/V, which is derived from the basic power equation P = IV.

2. How Does the Calculator Work?

The calculator uses the current equation:

Where:

• \( I \) — Current in Amperes (A)
• \( P \) — Power in Watts (W)
• \( V \) — Voltage in Volts (V)
• \( t \) — Time in seconds (s) [cancels out in the equation]

Explanation: The equation shows that current is directly proportional to power and inversely proportional to voltage. The time component cancels out in the calculation.

3. Importance of Current Calculation

Details: Calculating current is essential for circuit design, selecting appropriate wire gauges, determining fuse sizes, and ensuring electrical safety in systems.

4. Using the Calculator

Tips: Enter power in watts, voltage in volts, and time in seconds. All values must be positive numbers. The time input is included for dimensional consistency but cancels out in the calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why does time cancel out in the equation?
A: Time appears in both numerator and denominator, so it cancels out, showing current is an instantaneous relationship between power and voltage.

Q2: What are typical current values in household circuits?
A: In 120V systems, a 60W bulb draws about 0.5A, while a 1500W heater draws about 12.5A.

Q3: Does this work for both AC and DC circuits?
A: For DC and AC circuits with purely resistive loads, yes. For reactive AC loads, power factor must be considered.

Q4: What if I get a negative current value?
A: The calculator only accepts positive inputs. Negative current in real circuits indicates direction of flow.

Q5: How accurate is this calculation?
A: It's theoretically exact for ideal conditions. Real-world factors like resistance, temperature, and power factor may affect actual current.