# Decibel (power)

Electric power is the rate at which energy is transferred by a circuit. The symbol for power is P and it is measured in watt (W). The Watt is defined as one joule per second. Electric power is equal to the voltage multiplied by the current.

### Formulas

The following formula can be used to calculate the decibel value for two electric powers or one of the powers.

P _{in } is the symbol for the input power and is measured in watt (W).

P _{out } is the symbol for the output power and is measured in watt (W).

L is the symbol for the decibel value and is measured in dB.