a digital display apparatus monitors changes in a measurement value , e . g ., voltage or fuel load , and in response , controls the rate at which the display is updated , to prevent flicker . when changes in the measurement value are small in amplitude or resemble noise pulses , the response time of the display is slowed . however , when the changes in the measurement values are large in amplitude or appear to be noise - free , response time is quickened so that a correct value is rapidly displayed .