The difference between (the ratio) of the highest and lowest signal in an electronic circuit. Dynamic range measures the highest voltage, current or power compared to the lowest signal.
When the music CD first came out in the mid-1980s, its dynamic range was widely touted. The CD could more accurately record an orchestra's range of volume than a vinyl phonograph record, such as from the quietest passages to the loudest drums.
The difference between (the ratio) of the lightest and darkest elements on a printed or displayed image. A photo with a "high" dynamic range means that the image can contain both very bright and very dark areas. See HDR
and HDR for photos