Skip to main content
1 of 2
EM Fields
  • 17.6k
  • 2
  • 20
  • 23

The decibel simply specifies the ratio of the magnitudes of like quantities, and is never ambiguous because, for example, when referring to voltage, - or current, or weight, or pressure, or any other scalar:

$$ dB = 20 \log_{10} \frac{V1}{V2} $$

However, when time gets involved and movement of a force through time becomes power,

$$ dB = 10\log_{10} \frac{P1}{P2} $$

EM Fields
  • 17.6k
  • 2
  • 20
  • 23