Power in electrical circuits is an important idea to understand how electricity works.

In electrical engineering, power is the speed at which energy moves or changes form.

The unit we use to measure power is called a watt (W). One watt is equal to one joule of energy used in one second.

Here are some common units of power you should know:

1. Watt (W)

• What it is: The main unit of power in the International System of Units (SI).
• How to calculate it: You can find power using the formula P = IV. In this formula, P is power in watts, I is current in amperes (A), and V is voltage in volts (V).

2. Kilowatt (kW)

• What it is: A unit that equals 1,000 watts.
• Where it's used: It’s often used to measure how much power things like home appliances and big machines use.
• Conversion: 1 kW = 1,000 W.

3. Megawatt (MW)

• What it is: A unit that equals 1,000,000 watts or 1,000 kilowatts.
• Where it's used: You’ll find this unit in electrical generation and large power plants.
• Conversion: 1 MW = 1,000 kW = 1,000,000 W.

4. Horsepower (hp)

• What it is: A unit of power often used to describe how powerful engines are.
• Conversion: 1 hp is about 746 W. While it’s not an official SI unit, it’s still very common in engineering.

5. Volt-Amperes (VA)

• What it is: This unit measures apparent power in an electrical circuit.
• How it relates to Watts: In simple circuits, 1 VA equals 1 W. But in alternating current (AC) circuits, they can be different because of something called the power factor.

Knowing these different power units is really helpful. It lets you calculate and manage energy use in many situations, from basic electrical circuits to more complicated power systems.