Electrical Craft Helper (ECH) Practice Exam 2025 – Your All-in-One Guide to Exam Success!

The formula for calculating electrical power is derived from Ohm's law and the relationship between voltage, current, and resistance in an electrical circuit. The correct formula is Power (P) = Voltage (V) × Current (I).

In this formula, electrical power is measured in watts (W), voltage in volts (V), and current in amperes (A). This relationship shows how much electrical energy is consumed or transferred in a circuit. When voltage is applied across a circuit, it encourages current to flow, and the power is simply the product of these two quantities.

For example, if you know the voltage supply of a circuit and the amount of current flowing through it, you can easily calculate the total power usage by multiplying these two values together. This makes it an essential formula for various applications, such as sizing electrical components, calculating energy costs, and designing circuits.