Calculating the voltage when the power and current are known is crucial for various electrical applications. This relationship is expressed through a specific formula, which we will explore with practical examples.
The Formula: \( P = V \cdot I \)
To find the voltage, we rearrange the formula as follows:
\[ V = \dfrac{P}{I} \]
Where:
- \( P \) is the electric power (measured in watts, W)
- \( V \) is the voltage (measured in volts, V)
- \( I \) is the current (measured in amperes, A)
Example 1: Voltage of a Desktop Power Supply
Question: A desktop power supply provides 480 watts of power and 20 amperes of current. What is the voltage output?
Calculation:
Given:
- \( P = 480 \) W
- \( I = 20 \) A
Using the formula:
\[ V = \dfrac{P}{I} = \dfrac{480}{20} = 24 \, \text{V} \]
Result: The voltage output of the desktop power supply is 24 volts.
Example 2: Voltage of an Electric Motor
Question: An electric motor operates at 1500 watts and 30 amperes. What is the voltage across the motor?
Calculation:
Given:
- \( P = 1500 \) W
- \( I = 30 \) A
Using the formula:
\[ V = \dfrac{P}{I} = \dfrac{1500}{30} = 50 \, \text{V} \]
Result: The voltage across the electric motor is 50 volts.
Example 3: Voltage of a Battery Charger
Question: A battery charger provides 120 watts of power and 4 amperes of current. What is the voltage output?
Calculation:
Given:
- \( P = 120 \) W
- \( I = 4 \) A
Using the formula:
\[ V = \dfrac{P}{I} = \dfrac{120}{4} = 30 \, \text{V} \]
Result: The voltage output of the battery charger is 30 volts.
