How to define dB and how does it refer to power values?

[saif haider]

what dB shows us about the values on power how can i define dB

 

[echo47]

dB

A dB is a ratio between two values. It doesn't have any units. Perhaps you mean dBm (dB relative to a milliwatt), or something like that.

More info:
https://en.wikipedia.org/wiki/Decibel

 

[SSP]

Re: dB

a Decibel or dB is used for the logarithmic scale.
Sometimes,when we plot graphs,the range over whicha particular quantity should be plotted is very large.Say fro eg frequecy.u may not be able to plot frequencies ranging from Hz to GHz on the same graph.for this reason, we use a compressed scale,ie the logarithmic scale.

 

[lkuzu]

Re: dB

dB = 10*Log(Power/1W)

It shows how much power is below or above 1W. If power output is 1W, then it is 0 dB. If you double it, 2W means 3dB. dB makes the calculations easy because we don't multiply/divide the values, but we add or subtract dB values.

 

[IBO]

Re: dB

10log(P(u want)/P(any reference))