Wattage Calculator

How to Calculate Wattage

Calculating wattage is a fundamental skill in electrical engineering and physics. It helps us understand the relationship between power (watts), voltage (volts), current (amperes), and resistance (ohms) in an electrical circuit. By mastering these calculations, you can better analyze power consumption, design electrical systems, and troubleshoot electrical issues.

Wattage Formulas

There are several formulas to calculate wattage, depending on which values you know:

1. Using Voltage and Current

\[P = V \times I\]

2. Using Voltage and Resistance

\[P = \frac{V^2}{R}\]

3. Using Current and Resistance

\[P = I^2 \times R\]

Where:

• P is the power in watts (W)
• V is the voltage in volts (V)
• I is the current in amperes (A)
• R is the resistance in ohms (Ω)

Calculation Steps

1. Identify the known values (voltage, current, or resistance)
2. Choose the appropriate formula based on the known values
3. Plug the values into the formula
4. Calculate to find the wattage

Example Calculations

Example 1: Using Voltage and Current

Let's calculate the wattage for a circuit with 120 volts and 2 amperes:

1. Identify the given values:

   \[V = 120 \text{ V}\]

   \[I = 2 \text{ A}\]

2. Apply the formula:

   \[P = V \times I = 120 \text{ V} \times 2 \text{ A} = 240 \text{ W}\]

Therefore, the power consumption is 240 watts.

Example 2: Using Voltage and Resistance

Now, let's calculate the wattage for a circuit with 12 volts and 6 ohms resistance:

1. Identify the given values:

   \[V = 12 \text{ V}\]

   \[R = 6 \text{ Ω}\]

2. Apply the formula:

   \[P = \frac{V^2}{R} = \frac{(12 \text{ V})^2}{6 \text{ Ω}} = \frac{144}{6} = 24 \text{ W}\]

Therefore, the power consumption is 24 watts.

Calculation Visualization

This bar chart visually compares the input voltage (120 V), current (2 A), and the resulting power in watts (240 W) from our first example calculation. The height of each bar is proportional to its value, illustrating the relationship between volts, amperes, and watts in electrical calculations.