• # Decibel

The decibel is a standard unit for measuring relative levels of current, voltage, or power.

The decibel shows the ratio between the input and the output.

Decibel is abbreviated dB.

A minus sign before the dB indicates a loss and a plus sign or no sign at all before the dB indicates a gain.

## The Decibel Formula

The decibel value of a change between input and output can be expressed utilizing the following algorithm:

db = log10 Input / Output

## A Decibel Table

Decibel Gain Ratio of Gain
1 1.3
3 2.0
5 3.2
6 4.0
7 5.0
10 10
20 100
30 1,000
40 10,000
50 100,000
60 1,000,000

From this table, we can see that a gain of 3dB doubles the signal. Similarly, a loss of -3dB reduces the signal strength by half.

## Decibel Meters

A decibel meter (sound-level meter or loudness meter) is a device that measures and/or manipulates the loudness of an audio system or any other device that produces noise. Decibel meters are very common in industrial applications that require devices to produce a specific maximum noise, such as aircraft applications and audio devices. They are used in domestic applications in order to tune musical instruments, speakers, and power tools. Decibel meters can also be used in general outdoor applications to assess the loudness of background noise in a given area.

How Decibel Meters Work

A decibel meter measures the loudness of sound waves via a microphone and piezoelectric transducer. A piezoelectric transducer is a device, usually made of crystal or ceramic, that converts mechanical pressure in the form of vibrations into electricity, and electricity into mechanical pressure. As the microphone and piezoelectric transducer intercept sound waves, they are converted into electricity that electronic circuits monitor. As a result, decibel meters are often digital and have a variety of features.

Applications

The sound level that industrial environments produce is often regulated by law and must not exceed a specific intensity in order to protect laborers from being injured or deafened by the noise. Decibel meters allow employees to check devices that produce noise and allow individuals to measure the sound level of the area they are in. Decibel meters also allow aeronautical engineers to measure the sound level that aircraft and spacecraft produce, so that they do not damage or injure people in their path. Likewise, decibel meters allow aircraft to stay under a specific sound level in stealth missions so that they do not disturb the peace.