power

A decibel (dB) is 1/10th of a bel (B), so 10 decibel = 1 bel. A decibel value by itself does not mean anything. It expresses a ratio, typically of power or intensity, on a logarithmic scale.

In electronics, voltage and current amplification are calculated as 20 * log₁₀ and power as 10 * log₁₀. Logarithms are the inverse of exponentiation. For instance, the logarithm to the base 10 of a number is the power to which 10 must be raised to produce that number.