Power is an important idea in electrical circuits and devices.

It tells us how fast energy is used or changed.

We can calculate power using this simple formula:

$$P = \frac{W}{t}$$

Here, ( P ) stands for power in watts, ( W ) is the work done in joules, and ( t ) is the time in seconds.

1. Units of Power:

• The main unit for power is the watt (W).
• One watt is the same as one joule per second (1 W = 1 J/s).
• Other units include kilowatts (1 kW = 1000 W) and horsepower (1 hp is about 746 W).

2. Why Power Matters in Circuits:

• Power shows how much energy a device uses or makes.
• For example, a regular light bulb needs about 60 to 100 watts.
• An electric kettle, on the other hand, may use 2000 to 3000 watts.

3. Ohm’s Law and Power:

• We can also express power using voltage (V) and current (I) like this:

$$P = VI$$

• In simple circuits, we can use resistance (R) as well:

P = I^2R \quad \text{or} \quad P = \frac{V^2}{R}$$ Understanding power is helpful for many reasons. It can help us figure out energy costs, choose the best devices for efficiency, and make sure electrical parts work safely.