# dB

## Definitions

### Electronics

- A dimensionless logarithmic unit utilized to express the ratio of two powers or intensities, such as voltages, currents, or
__sound__ intensities. The number of decibels is equal to 10 times the __common logarithm__ of the ratio of the measured powers, or when comparing voltages, currents, or analogous acoustic quantities, it is 20 times the common logarithm. It is equal to 0.1 bels, or approximately 0.1151 nepers. - In
__acoustics__, the __sound pressure__ ratio that determines the relative intensity of sounds, against a __reference pressure__. Such a __pressure__ is usually defined as 20 micropascals, which is assigned a value of 0 decibels. Anything above this 0 decibels __threshold__ is considered to be audible. Before pain sets in, a person with good hearing can listen at 120 decibels, or 20 pascals, which is a __trillion__ times louder than 0 decibels. - chemical symbol fordubnium
(written as *Db*)

- synonymdecibel

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