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Electrical & Electronics Engineering vocabulary · Signals and Analog Electronics

Decibel

Meaning in electrical & electronics engineering, with examples

/ˈdɛsəˌbɛl/nounCommon term

In electrical & electronics engineering, decibel means: A logarithmic unit (dB) that compares two power or voltage levels. An increase of 3 dB roughly doubles the power, and 20 dB means ten times the voltage.

In Turkish: desibel, dB

How it is used

Written dB and often read 'dee-bee' in the lab. Used for gain, loss, noise, filters, antennas and sound levels. Engineers say a filter is '3 dB down' at its cutoff or a cable has '2 dB of loss'. Variants such as dBm, dBV and dBi use fixed reference levels.

Example sentences

  1. The new filter gives us about 40 decibels of attenuation at 1 MHz.

  2. The signal dropped by six decibels, which means the voltage has halved.

Common collocations

  • 3 dB point
  • gain in decibels
  • dB loss
  • decibel scale
  • gainThe ratio of a circuit's output to its input, showing how much it amplifies a signal. It can be given as a plain number, such as ×10, or in decibels.
  • noiseUnwanted random or interfering signals that mix with the signal you want and make it harder to measure or use. It can come from components, power supplies, motors or radio sources.
  • bandwidthThe range of frequencies a circuit, instrument or channel can handle well, usually up to the point where the signal falls by 3 dB. In communications it also means data capacity.
  • filterA circuit that lets some frequencies pass and blocks or weakens others. Common types are low-pass, high-pass, band-pass and notch filters.

More terms: Signals and Analog Electronics

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