How do you calculate delivered power?

Calculating Delivered Power

Electrical power, measured in watts (W), is a fundamental metric used to quantify the rate at which electrical energy is transferred or consumed. When an electrical circuit includes a resistor, the power dissipated by the resistor can be calculated using Ohm’s law.

Ohm’s Law and Power Dissipation

Ohm’s law establishes a direct relationship between voltage (V), current (I), and resistance (R) in an electrical circuit:

V = IR

where:

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

Ohm’s law can be rearranged to determine the power (P) dissipated by a resistor in an electrical circuit:

P = VI

where:

• P is the power in watts (W)
• V is the voltage across the resistor in volts (V)
• I is the current flowing through the resistor in amperes (A)

Example Calculation

Consider an electrical circuit with a resistor having a resistance of 10 ohms (Ω). If a voltage of 5 volts (V) is applied across the resistor, the current flowing through it can be calculated using Ohm’s law:

I = V / R = 5 V / 10 Ω = 0.5 A

The power dissipated by the resistor can then be calculated using the formula:

P = VI = 5 V × 0.5 A = 2.5 W

Therefore, the resistor in the given circuit dissipates 2.5 watts of electrical power.

Significance of Power Dissipation

Power dissipation is a critical consideration in electrical circuits, as excessive power dissipation can lead to overheating, component damage, and even fires. Resistors are commonly used to regulate current and voltage in circuits, but they also generate heat as a byproduct of their operation. Therefore, it is important to select resistors with appropriate power ratings to ensure safe and reliable circuit operation.