Power Relationships
Your everyday electrical devices all have one thing in common - they convert electrical energy into other forms like light, heat, or sound. Power tells us how quickly this energy conversion happens, and it's directly linked to current and voltage.
The fundamental relationship is P = IV, where P is power (measured in watts), I is current (amperes), and V is voltage (volts). Think of it this way: more current or higher voltage means more power being used.
There's another useful form: P = I²R. This comes from substituting V = IR into our original equation. This relationship is particularly handy when you know the current and resistance but not the voltage directly.
Quick Check: A 3A current flowing through a 4Ω resistor uses P = 3² × 4 = 36W of power.
