The amount of Power consumed by a device or drained from a generator is proportional to the product of the amount of current flowing through the device by the applied voltage.
Formula 1
P = V x I
Where:
P is the Power in watts (W)
V is the voltage in volts (V)
I is the amount of current (intensity) in amperes (A)
Derivated Formulas
Formula 2:
V = P/I
Formula 3:
I = P/V
Application Example:
Calculate the dissipated power by a resistor where a current of 200 mA flows when it is plugged to a 12 V power supply?
Data:
V = 12 V
I = 200 mA = 0,2 A
P = ?
Applying formula 1:
P = 12 x 0,2 = 2,4 W (or joules per second)
