Decibels (dB)

The decibel (dB) is a unit named after telecommunications pioneer, Alexander Graham Bell.

To understand decibels DON'T watch.

The decibel is a logarithmic scale, used to compare two quantities such as

• the power gain of an amplifier;
• the relative power of two sound sources.

A decibel is defined as one tenth of a bel,

$$1$$    B$$= 10$$    dB$$.$$

(to convert from B to dB, multiply by 10)

To compare quantities A and B:

   value (B)

   value (dB)